v2.8.2v2.8.2

* **Operations:**
   * Force validate all operations on execute if they haven't been before, if validation fails it will show the message error
   * Add some utility functions to ease layer and mat allocation in the file
   * Layer remove: Disallow to select and remove all layers
   * Tool - Edit print parameters: Retract speed wasn't propagating the value to normal layers
* File formats: Better control, set and checking for null/empty thumbnails

37 files changed, 353 insertions, 95 deletions

diff --git a/CHANGELOG.md b/CHANGELOG.md
index c67036f..e1d1a8c 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,9 +1,18 @@
 # Changelog
 
+## 05/04/2021 - v2.8.2
+
+* **Operations:**
+   * Force validate all operations on execute if they haven't been before, if validation fails it will show the message error
+   * Add some utility functions to ease layer and mat allocation in the file
+   * Layer remove: Disallow to select and remove all layers
+   * Tool - Edit print parameters: Retract speed wasn't propagating the value to normal layers 
+* File formats: Better control, set and checking for null/empty thumbnails
+
 ## 04/04/2021 - v2.8.1
 
 * Clipboard Manager: As now full backups are made when removing or adding layers, the undo and redo no longer rebuilds layer properties nor Z heights
-* Resin traps: Improved the detection to group areas with cross paths and process them as one whole area, this also increase the detection speed and performance (#179, #13 )
+* Resin traps: Improved the detection to group areas with cross paths and process them as one whole area, this also increase the detection speed and performance (#179, #13)
 * Action - Layer import: Fix a bug preventing to import layers of any kind
 
 ## 28/03/2021 - v2.8.0
diff --git a/UVtools.Core/Extensions/EmguExtensions.cs b/UVtools.Core/Extensions/EmguExtensions.cs
index a6aa974..48a9da8 100644
--- a/UVtools.Core/Extensions/EmguExtensions.cs
+++ b/UVtools.Core/Extensions/EmguExtensions.cs
@@ -298,5 +298,29 @@ namespace UVtools.Core.Extensions
             return newMat;
         }
 
+        /// <summary>
+        /// Allocates a new array of mat 's
+        /// </summary>
+        /// <param name="count">Array size</param>
+        /// <returns></returns>
+        public static Mat[] Allocate(uint count) => Allocate(count, Size.Empty);
+
+        /// <summary>
+        /// Allocates a new array of mat 's
+        /// </summary>
+        /// <param name="count">Array size</param>
+        /// <param name="size">Image size to create, use <see cref="Size.Empty"/> to create a empty Mat</param>
+        /// <returns>New mat array</returns>
+        public static Mat[] Allocate(uint count, Size size)
+        {
+            var layers = new Mat[count];
+            for (var i = 0; i < layers.Length; i++)
+            {
+                layers[i] = size == Size.Empty ? new Mat() : InitMat(size);
+            }
+
+            return layers;
+        }
+
     }
 }
diff --git a/UVtools.Core/FileFormats/ChituboxFile.cs b/UVtools.Core/FileFormats/ChituboxFile.cs
index 2e4949a..f317809 100644
--- a/UVtools.Core/FileFormats/ChituboxFile.cs
+++ b/UVtools.Core/FileFormats/ChituboxFile.cs
@@ -1302,7 +1302,7 @@ namespace UVtools.Core.FileFormats
 
                 if (HeaderSettings.EncryptionKey == 0)
                 {
-                    Random rnd = new Random();
+                    Random rnd = new();
                     HeaderSettings.EncryptionKey = (uint)rnd.Next(byte.MaxValue, int.MaxValue);
                 }
             }
@@ -1322,8 +1322,9 @@ namespace UVtools.Core.FileFormats
             for (byte i = 0; i < thumbnails.Length; i++)
             {
                 var image = thumbnails[i];
+                if(image is null) continue;
 
-                Preview preview = new Preview
+                Preview preview = new()
                 {
                     ResolutionX = (uint)image.Width,
                     ResolutionY = (uint)image.Height,
diff --git a/UVtools.Core/FileFormats/FileFormat.cs b/UVtools.Core/FileFormats/FileFormat.cs
index 86690fe..c36790d 100644
--- a/UVtools.Core/FileFormats/FileFormat.cs
+++ b/UVtools.Core/FileFormats/FileFormat.cs
@@ -458,7 +458,7 @@ namespace UVtools.Core.FileFormats
 
                 foreach (var thumbnail in Thumbnails)
                 {
-                    if (thumbnail is null) continue;
+                    if (thumbnail is null || thumbnail.IsEmpty) continue;
                     count++;
                 }
 
@@ -1194,7 +1194,7 @@ namespace UVtools.Core.FileFormats
         {
             for (int i = 0; i < ThumbnailsCount; i++)
             {
-                if(ReferenceEquals(Thumbnails[i], null)) continue;
+                if(Thumbnails[i] is null) continue;
                 if (Thumbnails[i].Height <= maxHeight) return Thumbnails[i];
             }
 
@@ -1232,9 +1232,18 @@ namespace UVtools.Core.FileFormats
         /// <param name="images"></param>
         public void SetThumbnails(Mat[] images)
         {
-            for (var i = 0; i < ThumbnailsCount; i++)
+            byte imageIndex = 0;
+            for (int i = 0; i < ThumbnailsCount; i++)
             {
-                Thumbnails[i] = images[Math.Min(i, images.Length - 1)].Clone();
+                var image = images[Math.Min(imageIndex++, images.Length - 1)];
+                if (image is null || image.IsEmpty)
+                {
+                    if (imageIndex >= images.Length) break;
+                    i--;
+                    continue;
+                }
+
+                Thumbnails[i] = image.Clone();
                 if (Thumbnails[i].Size != ThumbnailsOriginalSize[i])
                 {
                     CvInvoke.Resize(Thumbnails[i], Thumbnails[i], ThumbnailsOriginalSize[i]);
@@ -1248,6 +1257,7 @@ namespace UVtools.Core.FileFormats
         /// <param name="images">Image to set</param>
         public void SetThumbnails(Mat image)
         {
+            if (image is null || image.IsEmpty) return;
             for (var i = 0; i < ThumbnailsCount; i++)
             {
                 Thumbnails[i] = image.Clone();
@@ -1299,7 +1309,7 @@ namespace UVtools.Core.FileFormats
 
             for (var i = 0; i < Thumbnails.Length; i++)
             {
-                if (Thumbnails[i] is null) continue;
+                if (Thumbnails[i] is null || Thumbnails[i].IsEmpty) continue;
                 if(Thumbnails[i].Size == ThumbnailsOriginalSize[i]) continue;
                 CvInvoke.Resize(Thumbnails[i], Thumbnails[i], new Size(ThumbnailsOriginalSize[i].Width, ThumbnailsOriginalSize[i].Height));
             }
diff --git a/UVtools.Core/FileFormats/UVJFile.cs b/UVtools.Core/FileFormats/UVJFile.cs
index 222ded1..bc45523 100644
--- a/UVtools.Core/FileFormats/UVJFile.cs
+++ b/UVtools.Core/FileFormats/UVJFile.cs
@@ -163,7 +163,7 @@ namespace UVtools.Core.FileFormats
 
         public override byte ThumbnailsCount { get; } = 2;
 
-        public override System.Drawing.Size[] ThumbnailsOriginalSize { get; } = {new System.Drawing.Size(400, 400), new System.Drawing.Size(800, 480) };
+        public override System.Drawing.Size[] ThumbnailsOriginalSize { get; } = {new(400, 400), new(800, 480) };
 
         public override uint ResolutionX
         {
@@ -346,28 +346,20 @@ namespace UVtools.Core.FileFormats
 
                 if (CreatedThumbnailsCount > 0)
                 {
-                    using (Stream stream = outputFile.CreateEntry(FilePreviewTinyName).Open())
-                    {
-                        using (var vec = new VectorOfByte())
-                        {
-                            CvInvoke.Imencode(".png", Thumbnails[0], vec);
-                            stream.WriteBytes(vec.ToArray());
-                            stream.Close();
-                        }
-                    }
+                    using var stream = outputFile.CreateEntry(FilePreviewTinyName).Open();
+                    using var vec = new VectorOfByte();
+                    CvInvoke.Imencode(".png", Thumbnails[0], vec);
+                    stream.WriteBytes(vec.ToArray());
+                    stream.Close();
                 }
 
                 if (CreatedThumbnailsCount > 1)
                 {
-                    using (Stream stream = outputFile.CreateEntry(FilePreviewHugeName).Open())
-                    {
-                        using (var vec = new VectorOfByte())
-                        {
-                            CvInvoke.Imencode(".png", Thumbnails[1], vec);
-                            stream.WriteBytes(vec.ToArray());
-                            stream.Close();
-                        }
-                    }
+                    using Stream stream = outputFile.CreateEntry(FilePreviewHugeName).Open();
+                    using var vec = new VectorOfByte();
+                    CvInvoke.Imencode(".png", Thumbnails[1], vec);
+                    stream.WriteBytes(vec.ToArray());
+                    stream.Close();
                 }
 
                 for (uint layerIndex = 0; layerIndex < LayerCount; layerIndex++)
diff --git a/UVtools.Core/Layer/LayerManager.cs b/UVtools.Core/Layer/LayerManager.cs
index f64330b..e601878 100644
--- a/UVtools.Core/Layer/LayerManager.cs
+++ b/UVtools.Core/Layer/LayerManager.cs
@@ -431,6 +431,9 @@ namespace UVtools.Core
                                 case nameof(SlicerFile.LiftSpeed):
                                     layer.LiftSpeed = SlicerFile.LiftSpeed;
                                     break;
+                                case nameof(SlicerFile.RetractSpeed):
+                                    layer.RetractSpeed = SlicerFile.RetractSpeed;
+                                    break;
                                 case nameof(SlicerFile.LightOffDelay):
                                     layer.LightOffDelay = SlicerFile.LightOffDelay;
                                     break;
@@ -477,13 +480,16 @@ namespace UVtools.Core
 
         /// <summary>
         /// Set LiftHeight to 0 if previous and current have same PositionZ
+        /// <param name="zeroLightOffDelay">If true also set light off to 0, otherwise current value will be kept.</param>
         /// </summary>
-        public void SetNoLiftForSamePositionedLayers()
+        public void SetNoLiftForSamePositionedLayers(bool zeroLightOffDelay = false)
         {
             for (int layerIndex = 1; layerIndex < LayerCount; layerIndex++)
             {
-                if (this[layerIndex - 1].PositionZ != this[layerIndex].PositionZ) continue;
-                this[layerIndex].LiftHeight = 0;
+                var layer = this[layerIndex];
+                if (this[layerIndex - 1].PositionZ != layer.PositionZ) continue;
+                layer.LiftHeight = 0;
+                //if(zeroLightOffDelay) layer.LightOffDelay = 0;
             }
             SlicerFile?.RebuildGCode();
         }
@@ -1763,6 +1769,34 @@ namespace UVtools.Core
         public void ReallocateEnd(uint layerCount, bool initBlack = false) => ReallocateInsert(LayerCount, layerCount, initBlack);
 
         /// <summary>
+        /// Allocate layers from a Mat array
+        /// </summary>
+        /// <param name="mats"></param>
+        /// <returns>The new Layer array</returns>
+        public Layer[] AllocateFromMat(Mat[] mats)
+        {
+            var layers = new Layer[mats.Length];
+            Parallel.For(0L, mats.Length, i =>
+            {
+                layers[i] = new Layer((uint)i, mats[i], this);
+            });
+
+            return layers;
+        }
+
+        /// <summary>
+        /// Allocate layers from a Mat array and set them to the current file
+        /// </summary>
+        /// <param name="mats"></param>
+        /// /// <returns>The new Layer array</returns>
+        public Layer[] AllocateAndSetFromMat(Mat[] mats)
+        {
+            var layers = AllocateFromMat(mats);
+            Layers = layers;
+            return layers;
+        }
+
+        /// <summary>
         /// Clone this object
         /// </summary>
         /// <returns></returns>
@@ -1800,5 +1834,7 @@ namespace UVtools.Core
         }
 
         #endregion
+
+
     }
 }
diff --git a/UVtools.Core/Operations/Operation.cs b/UVtools.Core/Operations/Operation.cs
index f64f4c7..fc7de71 100644
--- a/UVtools.Core/Operations/Operation.cs
+++ b/UVtools.Core/Operations/Operation.cs
@@ -8,7 +8,6 @@
 
 using System;
 using System.Drawing;
-using System.Threading.Tasks;
 using System.Xml.Serialization;
 using Emgu.CV;
 using Emgu.CV.Util;
@@ -210,6 +209,12 @@ namespace UVtools.Core.Operations
         /// </summary>
         [XmlIgnore]
         public bool HaveExecuted { get; private set; }
+
+        /// <summary>
+        /// Gets if this operation have validated at least once
+        /// </summary>
+        [XmlIgnore]
+        public bool IsValidated { get; private set; }
         #endregion
 
         #region Constructor
@@ -224,16 +229,22 @@ namespace UVtools.Core.Operations
         #endregion
 
         #region Methods
+
+        public virtual string ValidateInternally() => null;
+
         /// <summary>
         /// Validates the operation
         /// </summary>
         /// <returns>null or empty if validates, otherwise return a string with error message</returns>
-        public virtual StringTag Validate(params object[] parameters) => null;
+        public string Validate()
+        {
+            IsValidated = true;
+            return ValidateInternally();
+        }
 
-        public bool CanValidate(params object[] parameters)
+        public bool CanValidate()
         {
-            var result = Validate(parameters);
-            return result is null || string.IsNullOrEmpty(result.Content);
+            return string.IsNullOrWhiteSpace(Validate());
         }
 
         public void SelectAllLayers()
@@ -383,7 +394,13 @@ namespace UVtools.Core.Operations
 
         public bool Execute(OperationProgress progress = null)
         {
-            if (_slicerFile is null) throw new InvalidOperationException($"{Title} can't execute due the lacking of file parent.");
+            if (_slicerFile is null) throw new InvalidOperationException($"{Title} can't execute due the lacking of a file parent.");
+            if (!IsValidated)
+            {
+                var msg = Validate();
+                if(!string.IsNullOrWhiteSpace(msg)) throw new InvalidOperationException($"{Title} can't execute due some errors:\n{msg}");
+            }
+
             progress ??= new OperationProgress();
             progress.Reset(ProgressAction, LayerRangeCount);
             HaveExecuted = true;
diff --git a/UVtools.Core/Operations/OperationArithmetic.cs b/UVtools.Core/Operations/OperationArithmetic.cs
index 75edfad..fd29f51 100644
--- a/UVtools.Core/Operations/OperationArithmetic.cs
+++ b/UVtools.Core/Operations/OperationArithmetic.cs
@@ -75,7 +75,7 @@ namespace UVtools.Core.Operations
 
         public override string ProgressAction => "Calculated layers";
 
-        public override StringTag Validate(params object[] parameters)
+        public override string ValidateInternally()
         {
             var sb = new StringBuilder();
             if (string.IsNullOrWhiteSpace(_sentence))
@@ -87,7 +87,7 @@ namespace UVtools.Core.Operations
             else if (Operations.Count == 0)
                 sb.AppendLine("No operations to perform.");
 
-            return new StringTag(sb.ToString());
+            return sb.ToString();
         }
 
         public override string ToString()
diff --git a/UVtools.Core/Operations/OperationBlur.cs b/UVtools.Core/Operations/OperationBlur.cs
index b68f447..ed65ac8 100644
--- a/UVtools.Core/Operations/OperationBlur.cs
+++ b/UVtools.Core/Operations/OperationBlur.cs
@@ -39,7 +39,7 @@ namespace UVtools.Core.Operations
 
         public override string ProgressAction => "Blured layers";
 
-        public override StringTag Validate(params object[] parameters)
+        public override string ValidateInternally()
         {
             var sb = new StringBuilder();
 
@@ -60,7 +60,7 @@ namespace UVtools.Core.Operations
                 }
             }
 
-            return new StringTag(sb.ToString());
+            return sb.ToString();
         }
 
         #endregion
diff --git a/UVtools.Core/Operations/OperationCalibrateElephantFoot.cs b/UVtools.Core/Operations/OperationCalibrateElephantFoot.cs
index 5da95f4..e9c2a03 100644
--- a/UVtools.Core/Operations/OperationCalibrateElephantFoot.cs
+++ b/UVtools.Core/Operations/OperationCalibrateElephantFoot.cs
@@ -75,7 +75,7 @@ namespace UVtools.Core.Operations
 
         public override string ProgressAction => "Generated";
 
-        public override StringTag Validate(params object[] parameters)
+        public override string ValidateInternally()
         {
             var sb = new StringBuilder();
 
@@ -94,7 +94,7 @@ namespace UVtools.Core.Operations
                 sb.AppendLine("No objects to output, please adjust the settings.");
             }
 
-            return new StringTag(sb.ToString());
+            return sb.ToString();
         }
 
         public override string ToString()
diff --git a/UVtools.Core/Operations/OperationCalibrateExposureFinder.cs b/UVtools.Core/Operations/OperationCalibrateExposureFinder.cs
index c57a03b..e9bdbb0 100644
--- a/UVtools.Core/Operations/OperationCalibrateExposureFinder.cs
+++ b/UVtools.Core/Operations/OperationCalibrateExposureFinder.cs
@@ -114,7 +114,7 @@ namespace UVtools.Core.Operations
 
         public override string ProgressAction => "Generated layers";
 
-        public override StringTag Validate(params object[] parameters)
+        public override string ValidateInternally()
         {
             var sb = new StringBuilder();
 
@@ -162,7 +162,7 @@ namespace UVtools.Core.Operations
                 }
             }
 
-            return new StringTag(sb.ToString());
+            return sb.ToString();
         }
 
         public override string ToString()
diff --git a/UVtools.Core/Operations/OperationCalibrateGrayscale.cs b/UVtools.Core/Operations/OperationCalibrateGrayscale.cs
index 215bccd..ec4e624 100644
--- a/UVtools.Core/Operations/OperationCalibrateGrayscale.cs
+++ b/UVtools.Core/Operations/OperationCalibrateGrayscale.cs
@@ -70,7 +70,7 @@ namespace UVtools.Core.Operations
 
         public override string ProgressAction => "Generated";
 
-        public override StringTag Validate(params object[] parameters)
+        public override string ValidateInternally()
         {
             var sb = new StringBuilder();
 
@@ -83,7 +83,7 @@ namespace UVtools.Core.Operations
                 sb.AppendLine("No divisions to output.");
             }
 
-            return new StringTag(sb.ToString());
+            return sb.ToString();
         }
 
         public override string ToString()
diff --git a/UVtools.Core/Operations/OperationCalibrateStressTower.cs b/UVtools.Core/Operations/OperationCalibrateStressTower.cs
index db0490e..4d9bcb8 100644
--- a/UVtools.Core/Operations/OperationCalibrateStressTower.cs
+++ b/UVtools.Core/Operations/OperationCalibrateStressTower.cs
@@ -64,7 +64,7 @@ namespace UVtools.Core.Operations
 
         public override string ProgressAction => "Generated";
 
-        public override StringTag Validate(params object[] parameters)
+        public override string ValidateInternally()
         {
             var sb = new StringBuilder();
 
@@ -78,7 +78,7 @@ namespace UVtools.Core.Operations
                 sb.AppendLine("Display height must be a positive value.");
             }
            
-            return new StringTag(sb.ToString());
+            return sb.ToString();
         }
 
         public override string ToString()
diff --git a/UVtools.Core/Operations/OperationCalibrateTolerance.cs b/UVtools.Core/Operations/OperationCalibrateTolerance.cs
index e73314a..2cc4d3a 100644
--- a/UVtools.Core/Operations/OperationCalibrateTolerance.cs
+++ b/UVtools.Core/Operations/OperationCalibrateTolerance.cs
@@ -76,7 +76,7 @@ namespace UVtools.Core.Operations
 
         public override string ProgressAction => "Generated";
 
-        public override StringTag Validate(params object[] parameters)
+        public override string ValidateInternally()
         {
             var sb = new StringBuilder();
 
@@ -100,7 +100,7 @@ namespace UVtools.Core.Operations
                 sb.AppendLine("No objects to output.");
             }
             
-            return new StringTag(sb.ToString());
+            return sb.ToString();
         }
 
         public override string ToString()
diff --git a/UVtools.Core/Operations/OperationCalibrateXYZAccuracy.cs b/UVtools.Core/Operations/OperationCalibrateXYZAccuracy.cs
index 40756dd..454bbbc 100644
--- a/UVtools.Core/Operations/OperationCalibrateXYZAccuracy.cs
+++ b/UVtools.Core/Operations/OperationCalibrateXYZAccuracy.cs
@@ -77,7 +77,7 @@ namespace UVtools.Core.Operations
 
         public override string ProgressAction => "Generated";
 
-        public override StringTag Validate(params object[] parameters)
+        public override string ValidateInternally()
         {
             var sb = new StringBuilder();
 
@@ -96,7 +96,7 @@ namespace UVtools.Core.Operations
                 sb.AppendLine("No objects to output.");
             }
             
-            return new StringTag(sb.ToString());
+            return sb.ToString();
         }
 
         public override string ToString()
diff --git a/UVtools.Core/Operations/OperationChangeResolution.cs b/UVtools.Core/Operations/OperationChangeResolution.cs
index c021753..e89aeab 100644
--- a/UVtools.Core/Operations/OperationChangeResolution.cs
+++ b/UVtools.Core/Operations/OperationChangeResolution.cs
@@ -74,7 +74,7 @@ namespace UVtools.Core.Operations
 
         public override string ProgressAction => "Changed layers";
 
-        public override StringTag Validate(params object[] parameters)
+        public override string ValidateInternally()
         {
             var sb = new StringBuilder();
             if (SlicerFile.ResolutionX == NewResolutionX && SlicerFile.ResolutionY == NewResolutionY)
@@ -88,7 +88,7 @@ namespace UVtools.Core.Operations
                 sb.AppendLine("To fix this, try to rotate the object and/or resize to fit on this new resolution.");
             }
 
-            return new StringTag(sb.ToString());
+            return sb.ToString();
         }
 
         public override string ToString()
diff --git a/UVtools.Core/Operations/OperationDynamicLayerHeight.cs b/UVtools.Core/Operations/OperationDynamicLayerHeight.cs
index 24930d6..9d123b4 100644
--- a/UVtools.Core/Operations/OperationDynamicLayerHeight.cs
+++ b/UVtools.Core/Operations/OperationDynamicLayerHeight.cs
@@ -95,7 +95,7 @@ namespace UVtools.Core.Operations
 
         public override string ProgressAction => "Processed layers";
 
-        public override StringTag Validate(params object[] parameters)
+        public override string ValidateInternally()
         {
             var sb = new StringBuilder();
 
@@ -141,7 +141,7 @@ namespace UVtools.Core.Operations
                 }
             }
 
-            return new StringTag(sb.ToString());
+            return sb.ToString();
         }
 
         public override string ToString()
diff --git a/UVtools.Core/Operations/OperationEditParameters.cs b/UVtools.Core/Operations/OperationEditParameters.cs
index b6da2c2..cb4ab3d 100644
--- a/UVtools.Core/Operations/OperationEditParameters.cs
+++ b/UVtools.Core/Operations/OperationEditParameters.cs
@@ -72,7 +72,7 @@ namespace UVtools.Core.Operations
 
         public override bool CanHaveProfiles => false;
 
-        public override StringTag Validate(params object[] parameters)
+        public override string ValidateInternally()
         {
             var sb = new StringBuilder();
             var changed = Modifiers.Any(modifier => modifier.HasChanged);
@@ -83,7 +83,7 @@ namespace UVtools.Core.Operations
             }
 
 
-            return new StringTag(sb.ToString());
+            return sb.ToString();
         }
         #endregion
 
diff --git a/UVtools.Core/Operations/OperationIPrintedThisFile.cs b/UVtools.Core/Operations/OperationIPrintedThisFile.cs
index c743aa7..76c1348 100644
--- a/UVtools.Core/Operations/OperationIPrintedThisFile.cs
+++ b/UVtools.Core/Operations/OperationIPrintedThisFile.cs
@@ -45,7 +45,7 @@ namespace UVtools.Core.Operations
 
         public override string ProgressAction => "Consumed";
 
-        public override StringTag Validate(params object[] parameters)
+        public override string ValidateInternally()
         {
             var sb = new StringBuilder();
 
@@ -62,7 +62,7 @@ namespace UVtools.Core.Operations
                 sb.AppendLine("Print time must be higher than 0s.");
             }
 
-            return new StringTag(sb.ToString());
+            return sb.ToString();
         }
 
         public override string ToString()
diff --git a/UVtools.Core/Operations/OperationLayerClone.cs b/UVtools.Core/Operations/OperationLayerClone.cs
index 9d12ab5..3b6fd8a 100644
--- a/UVtools.Core/Operations/OperationLayerClone.cs
+++ b/UVtools.Core/Operations/OperationLayerClone.cs
@@ -46,7 +46,7 @@ namespace UVtools.Core.Operations
 
         public override bool CanHaveProfiles => false;
 
-        public override StringTag Validate(params object[] parameters)
+        public override string ValidateInternally()
         {
             var sb = new StringBuilder();
             if (Clones <= 0)
@@ -54,7 +54,7 @@ namespace UVtools.Core.Operations
                 sb.AppendLine("Clones must be a positive number");
             }
 
-            return new StringTag(sb.ToString());
+            return sb.ToString();
         }
 
         public override string ToString()
diff --git a/UVtools.Core/Operations/OperationLayerImport.cs b/UVtools.Core/Operations/OperationLayerImport.cs
index 438cff4..fb69546 100644
--- a/UVtools.Core/Operations/OperationLayerImport.cs
+++ b/UVtools.Core/Operations/OperationLayerImport.cs
@@ -72,7 +72,7 @@ namespace UVtools.Core.Operations
 
         public override bool CanHaveProfiles => false;
 
-        public override StringTag Validate(params object[] parameters)
+        public override string ValidateInternally()
         {
             /*var result = new ConcurrentBag<StringTag>();
             Parallel.ForEach(Files, file =>
@@ -112,7 +112,7 @@ namespace UVtools.Core.Operations
                 sb.AppendLine("No files to import.");
             }
 
-            return new StringTag(sb.ToString());
+            return sb.ToString();
         }
         #endregion
 
diff --git a/UVtools.Core/Operations/OperationLayerReHeight.cs b/UVtools.Core/Operations/OperationLayerReHeight.cs
index 9d214f2..7b26095 100644
--- a/UVtools.Core/Operations/OperationLayerReHeight.cs
+++ b/UVtools.Core/Operations/OperationLayerReHeight.cs
@@ -44,7 +44,7 @@ namespace UVtools.Core.Operations
 
         public override bool CanHaveProfiles => false;
 
-        public override StringTag Validate(params object[] parameters)
+        public override string ValidateInternally()
         {
             var sb = new StringBuilder();
 
@@ -54,7 +54,7 @@ namespace UVtools.Core.Operations
             }
 
 
-            return new StringTag(sb.ToString());
+            return sb.ToString();
         }
 
         public override string ToString()
diff --git a/UVtools.Core/Operations/OperationLayerRemove.cs b/UVtools.Core/Operations/OperationLayerRemove.cs
index 653eef7..8ca7e3c 100644
--- a/UVtools.Core/Operations/OperationLayerRemove.cs
+++ b/UVtools.Core/Operations/OperationLayerRemove.cs
@@ -8,8 +8,10 @@
 
 using System;
 using System.Collections.Generic;
+using System.Text;
 using System.Threading.Tasks;
 using UVtools.Core.FileFormats;
+using UVtools.Core.Objects;
 
 namespace UVtools.Core.Operations
 {
@@ -39,6 +41,18 @@ namespace UVtools.Core.Operations
 
         public override bool CanHaveProfiles => false;
 
+        public override string ValidateInternally()
+        {
+            var sb = new StringBuilder();
+
+            if (LayerRangeCount == SlicerFile.LayerCount)
+            {
+                sb.AppendLine("You can't remove all layers from the file. Keep at least one.");
+            }
+
+            return sb.ToString();
+        }
+
         #endregion
 
         #region Properties
diff --git a/UVtools.Core/Operations/OperationMask.cs b/UVtools.Core/Operations/OperationMask.cs
index 4b43b5a..f3571fb 100644
--- a/UVtools.Core/Operations/OperationMask.cs
+++ b/UVtools.Core/Operations/OperationMask.cs
@@ -38,7 +38,7 @@ namespace UVtools.Core.Operations
 
         public override bool CanHaveProfiles => false;
 
-        public override StringTag Validate(params object[] parameters)
+        public override string ValidateInternally()
         {
             var sb = new StringBuilder();
             if (Mask is null)
@@ -46,7 +46,7 @@ namespace UVtools.Core.Operations
                 sb.AppendLine("The mask can not be empty.");
             }
 
-            return new StringTag(sb.ToString());
+            return sb.ToString();
         }
         #endregion
 
diff --git a/UVtools.Core/Operations/OperationMove.cs b/UVtools.Core/Operations/OperationMove.cs
index b2cbacf..5c84b1e 100644
--- a/UVtools.Core/Operations/OperationMove.cs
+++ b/UVtools.Core/Operations/OperationMove.cs
@@ -40,7 +40,7 @@ namespace UVtools.Core.Operations
 
         public override bool CanHaveProfiles => false;
 
-        public override StringTag Validate(params object[] parameters)
+        public override string ValidateInternally()
         {
             var sb = new StringBuilder();
 
@@ -49,7 +49,7 @@ namespace UVtools.Core.Operations
                 sb.AppendLine("Your parameters will put the model outside of build plate. Please adjust the location and margins.");
             }
 
-            return new StringTag(sb.ToString());
+            return sb.ToString();
         }
 
         public override string ToString()
diff --git a/UVtools.Core/Operations/OperationPattern.cs b/UVtools.Core/Operations/OperationPattern.cs
index 22398b3..15ac44d 100644
--- a/UVtools.Core/Operations/OperationPattern.cs
+++ b/UVtools.Core/Operations/OperationPattern.cs
@@ -49,7 +49,7 @@ namespace UVtools.Core.Operations
 
         public override bool CanHaveProfiles => false;
 
-        public override StringTag Validate(params object[] parameters)
+        public override string ValidateInternally()
         {
             var sb = new StringBuilder();
 
@@ -63,7 +63,7 @@ namespace UVtools.Core.Operations
                 sb.AppendLine("Your parameters will put the object outside of the build plate, please adjust the margins.");
             }
 
-            return new StringTag(sb.ToString());
+            return sb.ToString();
         }
 
         #endregion
diff --git a/UVtools.Core/Operations/OperationPixelDimming.cs b/UVtools.Core/Operations/OperationPixelDimming.cs
index 6f92bf0..f441064 100644
--- a/UVtools.Core/Operations/OperationPixelDimming.cs
+++ b/UVtools.Core/Operations/OperationPixelDimming.cs
@@ -70,7 +70,7 @@ namespace UVtools.Core.Operations
 
         public override string ProgressAction => "Dimmed layers";
 
-        public override StringTag Validate(params object[] parameters)
+        public override string ValidateInternally()
         {
             var sb = new StringBuilder();
             /*if (WallThicknessStart == 0 && WallsOnly)
@@ -100,7 +100,7 @@ namespace UVtools.Core.Operations
                         if (item.Pattern.Cols != bytes.Length)
                         {
                             sb.AppendLine($"Row {row + 1} have invalid number of pixels, the pattern must have equal pixel count per line, per defined on line 1");
-                            return new StringTag(sb.ToString());
+                            return sb.ToString();
                         }
                     }
 
@@ -113,7 +113,7 @@ namespace UVtools.Core.Operations
                         else
                         {
                             sb.AppendLine($"{bytes[col]} is a invalid number, use values from 0 to 255");
-                            return new StringTag(sb.ToString());
+                            return sb.ToString();
                         }
                     }
                 }
@@ -125,10 +125,10 @@ namespace UVtools.Core.Operations
             if (Pattern is null && AlternatePattern is null)
             {
                 sb.AppendLine("Either even or odd pattern must contain a valid matrix.");
-                return new StringTag(sb.ToString());
+                return sb.ToString();
             }
 
-            return new StringTag(sb.ToString());
+            return sb.ToString();
         }
         
         public override string ToString()
@@ -149,6 +149,16 @@ namespace UVtools.Core.Operations
 
         #region Properties
 
+        public uint WallThickness
+        {
+            get => _wallThicknessStart;
+            set
+            {
+                WallThicknessStart = value;
+                WallThicknessEnd = value;
+            }
+        }
+
         public uint WallThicknessStart
         {
             get => _wallThicknessStart;
diff --git a/UVtools.Core/Operations/OperationRedrawModel.cs b/UVtools.Core/Operations/OperationRedrawModel.cs
index 26e6630..06f2c77 100644
--- a/UVtools.Core/Operations/OperationRedrawModel.cs
+++ b/UVtools.Core/Operations/OperationRedrawModel.cs
@@ -50,7 +50,7 @@ namespace UVtools.Core.Operations
 
         public override string ProgressAction => "Redraw layers";
 
-        public override StringTag Validate(params object[] parameters)
+        public override string ValidateInternally()
         {
             var sb = new StringBuilder();
 
@@ -59,7 +59,7 @@ namespace UVtools.Core.Operations
                 sb.AppendLine("The selected file is not valid.");
             }
 
-            return new StringTag(sb.ToString());
+            return sb.ToString();
         }
 
 
diff --git a/UVtools.Core/Operations/OperationRepairLayers.cs b/UVtools.Core/Operations/OperationRepairLayers.cs
index fc37c87..ab0a5e5 100644
--- a/UVtools.Core/Operations/OperationRepairLayers.cs
+++ b/UVtools.Core/Operations/OperationRepairLayers.cs
@@ -50,7 +50,7 @@ namespace UVtools.Core.Operations
 
         public override bool CanHaveProfiles => false;
 
-        public override StringTag Validate(params object[] parameters)
+        public override string ValidateInternally()
         {
             var sb = new StringBuilder();
 
@@ -59,7 +59,7 @@ namespace UVtools.Core.Operations
                 sb.AppendLine("You must select at least one repair operation.");
             }
 
-            return new StringTag(sb.ToString());
+            return sb.ToString();
         }
         #endregion
 
diff --git a/UVtools.Core/Operations/OperationResize.cs b/UVtools.Core/Operations/OperationResize.cs
index ec81b4d..0565437 100644
--- a/UVtools.Core/Operations/OperationResize.cs
+++ b/UVtools.Core/Operations/OperationResize.cs
@@ -44,7 +44,7 @@ namespace UVtools.Core.Operations
 
         public override string ProgressAction => "Resized layers";
 
-        public override StringTag Validate(params object[] parameters)
+        public override string ValidateInternally()
         {
             var sb = new StringBuilder();
 
@@ -53,7 +53,7 @@ namespace UVtools.Core.Operations
                 sb.AppendLine("X and Y can't both be 100%.");
             }
 
-            return new StringTag(sb.ToString());
+            return sb.ToString();
         }
         #endregion
 
diff --git a/UVtools.Core/Operations/OperationScripting.cs b/UVtools.Core/Operations/OperationScripting.cs
index 7807d16..661daad 100644
--- a/UVtools.Core/Operations/OperationScripting.cs
+++ b/UVtools.Core/Operations/OperationScripting.cs
@@ -48,15 +48,15 @@ namespace UVtools.Core.Operations
 
         public override string ProgressAction => "Scripted layers";
 
-        public override StringTag Validate(params object[] parameters)
+        public override string ValidateInternally()
         {
             if (!CanExecute)
             {
-                return new StringTag("Script is not loaded.");
+                return "Script is not loaded.";
             }
 
             var scriptValidation = _scriptState.ContinueWithAsync<string>("return ScriptValidate();").Result;
-            return new StringTag(scriptValidation.ReturnValue);
+            return scriptValidation.ReturnValue;
         }
 
         #endregion
diff --git a/UVtools.Core/UVtools.Core.csproj b/UVtools.Core/UVtools.Core.csproj
index 9d550de..6893a21 100644
--- a/UVtools.Core/UVtools.Core.csproj
+++ b/UVtools.Core/UVtools.Core.csproj
@@ -10,7 +10,7 @@
     <RepositoryUrl>https://github.com/sn4k3/UVtools</RepositoryUrl>
     <PackageProjectUrl>https://github.com/sn4k3/UVtools</PackageProjectUrl>
     <Description>MSLA/DLP, file analysis, calibration, repair, conversion and manipulation</Description>
-    <Version>2.8.1</Version>
+    <Version>2.8.2</Version>
     <Copyright>Copyright © 2020 PTRTECH</Copyright>
     <PackageIcon>UVtools.png</PackageIcon>
     <Platforms>AnyCPU;x64</Platforms>
diff --git a/UVtools.ScriptSample/ScriptTestPerLayerSettingsSample.cs b/UVtools.ScriptSample/ScriptTestPerLayerSettingsSample.cs
new file mode 100644
index 0000000..70e283c
--- /dev/null
+++ b/UVtools.ScriptSample/ScriptTestPerLayerSettingsSample.cs
@@ -0,0 +1,144 @@
+/*
+ *                     GNU AFFERO GENERAL PUBLIC LICENSE
+ *                       Version 3, 19 November 2007
+ *  Copyright (C) 2007 Free Software Foundation, Inc. <https://fsf.org/>
+ *  Everyone is permitted to copy and distribute verbatim copies
+ *  of this license document, but changing it is not allowed.
+ */
+
+using System;
+using System.Drawing;
+using Emgu.CV;
+using Emgu.CV.CvEnum;
+using UVtools.Core.Extensions;
+using UVtools.Core.Operations;
+using UVtools.Core.Scripting;
+
+namespace UVtools.ScriptSample
+{
+    /// <summary>
+    /// Change layer properties to random values
+    /// </summary>
+    public class ScriptTestPerLayerSettingsSample : ScriptGlobals
+    {
+        private ScriptCheckBoxInput InputDoNotUseLift = new()
+        {
+            Label = "Do not perform the lift sequence for same height layers",
+            ToolTip = "Not all printers are compatible with this even if they can maintain same Z position, some will require a obligatory lift/retract",
+            Value = true
+        };
+
+        /// <summary>
+        /// Set configurations here, this function trigger just after load a script
+        /// </summary>
+        public void ScriptInit()
+        {
+            Script.Name = "Test per layer settings capability with a print";
+            Script.Description = "Print this file to check if your printer is able to have per layer independent settings.\n" +
+                                 "1) Load a file that you previous printed into UVtools\n" +
+                                 "2) Run this script\n" +
+                                 "3) Go to File -> Save As, and give it a new name\n" +
+                                 "4) Remove printer VAT and head/plate\n" +
+                                 "5) Print the created file and observe the printer LCD and movements:\n" +
+                                 "- First layer must show the whole face and do the normal lift sequence and raise to the next layer.\n" +
+                                 "- Then all the renaming layers should print one object per layer at same height, if not, then your printer is not able.\n" +
+                                 "Note: Look at printer screen to confirm the layer position, exposure time is set to 5s.\n" +
+                                 "If you find yours compatible and not on the official list, please report to us.\n" +
+                                 "https://github.com/sn4k3/UVtools/wiki/Printer-compability-with-per-layer-settings-and-advanced-tools";
+            Script.Author = "Tiago Conceição";
+            Script.Version = new Version(0, 1);
+            Script.UserInputs.Add(InputDoNotUseLift);
+        }
+
+        /// <summary>
+        /// Validate user inputs here, this function trigger when user click on execute
+        /// </summary>
+        /// <returns>A error message, empty or null if validation passes.</returns>
+        public string ScriptValidate()
+        {
+            return null;
+        }
+
+        /// <summary>
+        /// Execute the script, this function trigger when when user click on execute and validation passes
+        /// </summary>
+        /// <returns>True if executes successfully to the end, otherwise false.</returns>
+        public bool ScriptExecute()
+        {
+            const byte layerCount = 5;
+            const ushort eyeDiameter = 300;
+            const ushort noseHeight = eyeDiameter;
+            const ushort noseThickness = 100;
+            const ushort mouthHeight = 300;
+            const ushort faceSpacing = 150;
+            const LineType lineType = LineType.AntiAlias;
+            Progress.Reset("Generating layers", layerCount); // Sets the progress name and number of items to process
+
+            // Layer 0 = Whole face
+            // Layer 1 = Left eye
+            // Layer 2 = Nose
+            // Layer 3 = Right eye
+            // Layer 4 = Mouth
+            // Exercise for you: Do eyebrows
+            var mats = EmguExtensions.Allocate(layerCount, SlicerFile.Resolution); // Allocate x images with file resolution
+
+            int x, y;
+            int xCenter = (int) (SlicerFile.ResolutionX / 2);
+            //int yCenter = (int) (SlicerFile.ResolutionY / 2);
+
+            // Do the left eye
+            x = xCenter - noseThickness/2 - faceSpacing - eyeDiameter/2;
+            y = faceSpacing;
+            CvInvoke.Circle(mats[0], new Point(x, y), eyeDiameter/2, EmguExtensions.WhiteByte, -1, lineType);
+            CvInvoke.Circle(mats[1], new Point(x, y), eyeDiameter/2, EmguExtensions.WhiteByte, -1, lineType);
+            Progress++;
+
+            // Do the right eye, the mirror of left...
+            x = (int)(SlicerFile.ResolutionX - x);
+            CvInvoke.Circle(mats[0], new Point(x, y), eyeDiameter / 2, EmguExtensions.WhiteByte, -1, lineType);
+            CvInvoke.Circle(mats[3], new Point(x, y), eyeDiameter / 2, EmguExtensions.WhiteByte, -1, lineType);
+            Progress++;
+
+            // Do the noose
+            x = xCenter - noseThickness / 2;
+            CvInvoke.Rectangle(mats[0], new Rectangle(x, y, noseThickness, noseHeight), EmguExtensions.WhiteByte, -1, lineType);
+            CvInvoke.Rectangle(mats[2], new Rectangle(x, y, noseThickness, noseHeight), EmguExtensions.WhiteByte, -1, lineType);
+            Progress++;
+
+            // Do the mouth
+            x = xCenter;
+            y += noseHeight + faceSpacing;
+            CvInvoke.Ellipse(mats[0], new Point(x, y), new Size(eyeDiameter+faceSpacing+noseThickness/2, mouthHeight), 0, 0, 180, EmguExtensions.WhiteByte, -1, lineType);
+            CvInvoke.Ellipse(mats[4], new Point(x, y), new Size(eyeDiameter+faceSpacing+noseThickness/2, mouthHeight), 0, 0, 180, EmguExtensions.WhiteByte, -1, lineType);
+
+            SlicerFile.LayerManager.AllocateAndSetFromMat(mats); // Replace layers and rebuild properties
+
+            SlicerFile.BottomLayerCount = 1;    // Set one bottom layer, the whole face
+            SlicerFile.BottomExposureTime = 5;  // Set exposure to be fixed at 5s
+            SlicerFile.ExposureTime = 5;        // Set exposure to be fixed at 5s
+
+            // Set layers 2-4 all same z height as layer 1
+            for (int layerIndex = 2; layerIndex < mats.Length; layerIndex++)
+            {
+                SlicerFile[layerIndex].PositionZ = SlicerFile[1].PositionZ;
+            }
+
+            if (InputDoNotUseLift.Value)
+            {
+                SlicerFile.LayerManager.SetNoLiftForSamePositionedLayers();
+            }
+            Progress++;
+
+            // Move me to the middle
+            new OperationMove(SlicerFile).Execute(Progress);
+
+            // Generate a cool waves pattern, just because i can :)
+            var pdOp = new OperationPixelDimming(SlicerFile) {WallThickness = 25};
+            pdOp.GenerateInfill("Waves");
+            pdOp.Execute(Progress);
+
+            // return true if not cancelled by user
+            return !Progress.Token.IsCancellationRequested;
+        }
+    }
+}
diff --git a/UVtools.WPF/Controls/Tools/ToolScriptingControl.axaml.cs b/UVtools.WPF/Controls/Tools/ToolScriptingControl.axaml.cs
index eaa58db..eaff935 100644
--- a/UVtools.WPF/Controls/Tools/ToolScriptingControl.axaml.cs
+++ b/UVtools.WPF/Controls/Tools/ToolScriptingControl.axaml.cs
@@ -103,9 +103,9 @@ namespace UVtools.WPF.Controls.Tools
             TextBox tbScriptName = new()
             {
                 IsReadOnly = true,
-                Text = $"{Operation.ScriptGlobals.Script.Name} v{Operation.ScriptGlobals.Script.Version} by {Operation.ScriptGlobals.Script.Author}",
+                Text = $"{Operation.ScriptGlobals.Script.Name} | Version: {Operation.ScriptGlobals.Script.Version} by {Operation.ScriptGlobals.Script.Author}",
                 UseFloatingWatermark = true,
-                Watermark = "Script name, Version and Author"
+                Watermark = "Script name, version and author"
             };
 
             TextBox tbScriptDescription = new()
diff --git a/UVtools.WPF/MainWindow.Information.cs b/UVtools.WPF/MainWindow.Information.cs
index 7e35a3c..3822b94 100644
--- a/UVtools.WPF/MainWindow.Information.cs
+++ b/UVtools.WPF/MainWindow.Information.cs
@@ -128,7 +128,7 @@ namespace UVtools.WPF
                 if (!IsFileLoaded) return;
                 var index = value - 1;
                 if (index >= SlicerFile.CreatedThumbnailsCount) return;
-                if (SlicerFile.Thumbnails[index] is null) return;
+                if (SlicerFile.Thumbnails[index] is null || SlicerFile.Thumbnails[index].IsEmpty) return;
                 if (!RaiseAndSetIfChanged(ref _visibleThumbnailIndex, value)) return;
 
                 VisibleThumbnailImage = SlicerFile.Thumbnails[index].ToBitmap();
diff --git a/UVtools.WPF/Program.cs b/UVtools.WPF/Program.cs
index 57293c9..2261565 100644
--- a/UVtools.WPF/Program.cs
+++ b/UVtools.WPF/Program.cs
@@ -2,6 +2,7 @@
 using System.Diagnostics;
 using System.Runtime.ExceptionServices;
 using Avalonia;
+using UVtools.WPF.Extensions;
 
 namespace UVtools.WPF
 {
@@ -31,12 +32,12 @@ namespace UVtools.WPF
         }
 
 
-        private static void CurrentDomainOnUnhandledException(object sender, UnhandledExceptionEventArgs e)
+        private static async void CurrentDomainOnUnhandledException(object sender, UnhandledExceptionEventArgs e)
         {
             Exception ex = (Exception)e.ExceptionObject;
             ErrorLog.AppendLine("Fatal Non-UI Error", ex.ToString());
-            
-            /*try
+
+            try
             {
                 string errorMsg = "An application error occurred. Please contact the administrator with the following information:\n\n" +
                                   $"{ex}";
@@ -46,7 +47,7 @@ namespace UVtools.WPF
             catch (Exception exception)
             {
                 Debug.WriteLine(exception);
-            }*/
+            }
         }
 
         // Avalonia configuration, don't remove; also used by visual designer.
diff --git a/UVtools.WPF/UVtools.WPF.csproj b/UVtools.WPF/UVtools.WPF.csproj
index 4e847ca..e6a7ed6 100644
--- a/UVtools.WPF/UVtools.WPF.csproj
+++ b/UVtools.WPF/UVtools.WPF.csproj
@@ -12,7 +12,7 @@
     <PackageLicenseFile>LICENSE</PackageLicenseFile>
     <RepositoryUrl>https://github.com/sn4k3/UVtools</RepositoryUrl>
     <RepositoryType>Git</RepositoryType>
-    <Version>2.8.1</Version>
+    <Version>2.8.2</Version>
   </PropertyGroup>
   
   <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug|AnyCPU'">