Merge pull request #8044 from mono/backport-pr-8032-to-release-8.2

[release-8.2] Adds a ZOrder system based in GtkNSViewHost

14 files changed, 133 insertions, 263 deletions

diff --git a/main/src/addins/MonoDevelop.DesignerSupport/MonoDevelop.DesignerSupport.Toolbox/MacToolbox.cs b/main/src/addins/MonoDevelop.DesignerSupport/MonoDevelop.DesignerSupport.Toolbox/MacToolbox.cs
index cc7f53b0a3..d94a8bbc68 100644
--- a/main/src/addins/MonoDevelop.DesignerSupport/MonoDevelop.DesignerSupport.Toolbox/MacToolbox.cs
+++ b/main/src/addins/MonoDevelop.DesignerSupport/MonoDevelop.DesignerSupport.Toolbox/MacToolbox.cs
@@ -41,13 +41,6 @@ using MonoDevelop.Components.Mac;
 
 namespace MonoDevelop.DesignerSupport.Toolbox
 {
-	interface INativeChildView
-	{
-		event EventHandler Focused;
-		void OnKeyPressed (object o, Gtk.KeyPressEventArgs ev);
-		void OnKeyReleased (object o, Gtk.KeyReleaseEventArgs ev);
-	}
-
 	class MacToolbox : NSStackView, IPropertyPadProvider, IToolboxConfiguration
 	{
 		const string ToolboxItemContextMenuCommand = "/MonoDevelop/DesignerSupport/ToolboxItemContextMenu";
@@ -60,7 +53,6 @@ namespace MonoDevelop.DesignerSupport.Toolbox
 		public event EventHandler DragBegin;
 		public event EventHandler DragSourceUnset;
 		public event EventHandler<Gtk.TargetEntry []> DragSourceSet;
-		public event EventHandler ContentFocused;
 
 		public ItemToolboxNode SelectedNode => toolboxWidget.SelectedItem?.Node;
 
@@ -108,10 +100,8 @@ namespace MonoDevelop.DesignerSupport.Toolbox
 			filterEntry.AccessibilityTitle = GettextCatalog.GetString ("Search Toolbox");
 			filterEntry.AccessibilityHelp = GettextCatalog.GetString ("Enter a term to search for it in the toolbox");
 			filterEntry.Activated += FilterTextChanged;
-			filterEntry.Focused += FilterEntry_Focused;
 
 			horizontalStackView.AddArrangedSubview (filterEntry);
-			AddWidgetToFocusChain (filterEntry);
 
 			filterEntry.SetContentCompressionResistancePriority ((int)NSLayoutPriority.DefaultLow, NSLayoutConstraintOrientation.Horizontal);
 			filterEntry.SetContentHuggingPriorityForOrientation ((int)NSLayoutPriority.DefaultLow, NSLayoutConstraintOrientation.Horizontal);
@@ -122,10 +112,8 @@ namespace MonoDevelop.DesignerSupport.Toolbox
 			catToggleButton.ToolTip = GettextCatalog.GetString ("Show categories");
 			catToggleButton.AccessibilityHelp = GettextCatalog.GetString ("Toggle to show categories");
 			catToggleButton.Activated += ToggleCategorisation;
-			catToggleButton.Focused += CatToggleButton_Focused;
 
 			horizontalStackView.AddArrangedSubview (catToggleButton);
-			AddWidgetToFocusChain (catToggleButton);
 
 			catToggleButton.SetContentCompressionResistancePriority ((int)NSLayoutPriority.DefaultHigh, NSLayoutConstraintOrientation.Horizontal);
 			catToggleButton.SetContentHuggingPriorityForOrientation ((int)NSLayoutPriority.DefaultHigh, NSLayoutConstraintOrientation.Horizontal);
@@ -136,10 +124,8 @@ namespace MonoDevelop.DesignerSupport.Toolbox
 			compactModeToggleButton.AccessibilityTitle = GettextCatalog.GetString ("Compact Layout");
 			compactModeToggleButton.AccessibilityHelp = GettextCatalog.GetString ("Toggle for toolbox to use compact layout");
 			compactModeToggleButton.Activated += ToggleCompactMode;
-			compactModeToggleButton.Focused += CompactModeToggleButton_Focused;
 
 			horizontalStackView.AddArrangedSubview (compactModeToggleButton);
-			AddWidgetToFocusChain (compactModeToggleButton);
 
 			compactModeToggleButton.SetContentCompressionResistancePriority ((int)NSLayoutPriority.DefaultHigh, NSLayoutConstraintOrientation.Horizontal);
 			compactModeToggleButton.SetContentHuggingPriorityForOrientation ((int)NSLayoutPriority.DefaultHigh, NSLayoutConstraintOrientation.Horizontal);
@@ -150,10 +136,8 @@ namespace MonoDevelop.DesignerSupport.Toolbox
 			toolboxAddButton.AccessibilityHelp = GettextCatalog.GetString ("Add toolbox items");
 			toolboxAddButton.ToolTip = GettextCatalog.GetString ("Add toolbox items");
 			toolboxAddButton.Activated += ToolboxAddButton_Clicked;
-			toolboxAddButton.Focused += ToolboxAddButton_Focused;
 
 			horizontalStackView.AddArrangedSubview (toolboxAddButton);
-			AddWidgetToFocusChain (toolboxAddButton);
 
 			toolboxAddButton.SetContentCompressionResistancePriority ((int)NSLayoutPriority.DefaultHigh, NSLayoutConstraintOrientation.Horizontal);
 			toolboxAddButton.SetContentHuggingPriorityForOrientation ((int)NSLayoutPriority.DefaultHigh, NSLayoutConstraintOrientation.Horizontal);
@@ -163,7 +147,6 @@ namespace MonoDevelop.DesignerSupport.Toolbox
 			toolboxWidget = new MacToolboxWidget (container) {
 				AccessibilityTitle = GettextCatalog.GetString ("Toolbox Toolbar"),
 			};
-			AddWidgetToFocusChain (toolboxWidget);
 
 			var scrollView = new NSScrollView () {
 				HasVerticalScroller = true,
@@ -181,7 +164,6 @@ namespace MonoDevelop.DesignerSupport.Toolbox
 			filterEntry.Changed += FilterEntry_Changed;
 
 			toolboxWidget.DragBegin += ToolboxWidget_DragBegin;
-			toolboxWidget.MouseDownActivated += ToolboxWidget_MouseDownActivated;
 			toolboxWidget.ActivateSelectedItem += ToolboxWidget_ActivateSelectedItem;
 			toolboxWidget.MenuOpened += ToolboxWidget_MenuOpened;
 			toolboxWidget.RegionCollapsed += FilterTextChanged;
@@ -216,26 +198,6 @@ namespace MonoDevelop.DesignerSupport.Toolbox
 			Refilter ();
 		}
 
-		void ToolboxAddButton_Focused (object sender, EventArgs e)
-		{
-			ChangeFocusedView (sender as INativeChildView);
-		}
-
-		void CompactModeToggleButton_Focused (object sender, EventArgs e)
-		{
-			ChangeFocusedView (sender as INativeChildView);
-		}
-
-		void CatToggleButton_Focused (object sender, EventArgs e)
-		{
-			ChangeFocusedView (sender as INativeChildView);
-		}
-
-		void FilterEntry_Focused (object sender, EventArgs e)
-		{
-			ChangeFocusedView (sender as INativeChildView);
-		}
-
 		void ToolboxWidget_DragBegin (object sender, EventArgs e)
 		{
 			if (this.toolboxWidget.SelectedItem != null) {
@@ -243,116 +205,6 @@ namespace MonoDevelop.DesignerSupport.Toolbox
 			}
 		}
 
-		void ToolboxWidget_MouseDownActivated (NSEvent obj)
-		{
-			ContentFocused?.Invoke (this, EventArgs.Empty);
-		}
-
-		internal void FocusSelectedView ()
-		{
-			if (Window == null) {
-				return;
-			}
-			if (FocusedView is NSView focusView && Window.FirstResponder != focusView && focusView.AcceptsFirstResponder ()) {
-				Window.MakeFirstResponder (focusView);
-			}
-		}
-
-		public override bool BecomeFirstResponder ()
-		{
-			return false;
-		}
-
-		#region Focus Chain
-
-		int focusedViewIndex = -1;
-		INativeChildView FocusedView => focusedViewIndex == -1 ? null : responderViewChain [focusedViewIndex];
-		List<INativeChildView> responderViewChain = new List<INativeChildView> ();
-	
-		void AddWidgetToFocusChain (INativeChildView view)
-		{
-			if (responderViewChain.Contains (view)) {
-				return;
-			}
-			responderViewChain.Add (view);
-			view.Focused -= View_Focused;
-			view.Focused += View_Focused;
-
-			if (focusedViewIndex == -1) {
-				focusedViewIndex = 0;
-			}
-		}
-
-		void View_Focused (object sender, EventArgs e)
-		{
-			ChangeFocusedView (sender as INativeChildView);
-		}
-
-		void ChangeFocusedView (INativeChildView view)
-		{
-			var index = responderViewChain.IndexOf (view);
-			if (index != -1)
-				focusedViewIndex = index;
-		}
-
-		void FocusPreviousItem (GLib.SignalArgs ev)
-		{
-			if (focusedViewIndex <= 0) {
-				//leave element
-				Window.ResignFirstResponder ();
-				if (ev != null) {
-					ev.RetVal = false;
-				}
-			} else {
-				focusedViewIndex--;
-				if (((NSView)FocusedView).Hidden) {
-					FocusPreviousItem (ev);
-				} else {
-					Window.MakeFirstResponder ((NSView)FocusedView);
-				}
-			}
-		}
-
-		void FocusNextItem (GLib.SignalArgs ev)
-		{
-			if (focusedViewIndex >= responderViewChain.Count - 1) {
-				//leave element
-				Window.ResignFirstResponder ();
-				if (ev != null) {
-					ev.RetVal = false;
-				}
-			} else {
-				focusedViewIndex++;
-				if (((NSView)FocusedView).Hidden) {
-					FocusNextItem (ev);
-				} else {
-					Window.MakeFirstResponder ((NSView)FocusedView);
-				}
-			}
-		}
-
-		#endregion
-
-		internal void KeyReleased (object o, Gtk.KeyReleaseEventArgs ev)
-		{
-			ev.RetVal = true;
-		}
-
-		internal void OnKeyPressed (object o, Gtk.KeyPressEventArgs ev)
-		{
-			ev.RetVal = true;
-			if (ev.Event.Key == Gdk.Key.Tab || ev.Event.Key == Gdk.Key.ISO_Left_Tab) {
-				if (ev.Event.State == Gdk.ModifierType.ShiftMask) {
-					FocusPreviousItem (ev);
-				} else {
-					FocusNextItem (ev);
-				}
-				return;
-			}
-
-			FocusedView?.OnKeyPressed (o, ev);
-		}
-
 		#region Toolbar event handlers
 
 		void ToggleCompactMode (object sender, EventArgs e)
@@ -528,20 +380,15 @@ namespace MonoDevelop.DesignerSupport.Toolbox
 		{
 			if (disposing) {
 				filterEntry.Activated -= FilterTextChanged;
-				filterEntry.Focused -= FilterEntry_Focused;
 
 				catToggleButton.Activated -= ToggleCategorisation;
-				catToggleButton.Focused -= CatToggleButton_Focused;
 
 				compactModeToggleButton.Activated -= ToggleCompactMode;
-				compactModeToggleButton.Focused -= CompactModeToggleButton_Focused;
 
 				toolboxAddButton.Activated -= ToolboxAddButton_Clicked;
-				toolboxAddButton.Focused -= ToolboxAddButton_Focused;
 
 				toolboxWidget.ActivateSelectedItem -= ToolboxWidget_ActivateSelectedItem;
 				toolboxWidget.MenuOpened -= ToolboxWidget_MenuOpened;
-				toolboxWidget.MouseDownActivated -= ToolboxWidget_MouseDownActivated;
 				toolboxWidget.DragBegin -= ToolboxWidget_DragBegin;
 				toolboxWidget.RegionCollapsed -= FilterTextChanged;
 
diff --git a/main/src/addins/MonoDevelop.DesignerSupport/MonoDevelop.DesignerSupport.Toolbox/MacToolboxWidget.cs b/main/src/addins/MonoDevelop.DesignerSupport/MonoDevelop.DesignerSupport.Toolbox/MacToolboxWidget.cs
index d8a6c9b2ce..519721942e 100644
--- a/main/src/addins/MonoDevelop.DesignerSupport/MonoDevelop.DesignerSupport.Toolbox/MacToolboxWidget.cs
+++ b/main/src/addins/MonoDevelop.DesignerSupport/MonoDevelop.DesignerSupport.Toolbox/MacToolboxWidget.cs
@@ -39,7 +39,7 @@ using MonoDevelop.Components.Mac;
 namespace MonoDevelop.DesignerSupport.Toolbox
 {
 	[Register ("MacToolboxWidget")]
-	class MacToolboxWidget : NSCollectionView, IToolboxWidget, INativeChildView
+	class MacToolboxWidget : NSCollectionView, IToolboxWidget
 	{
 		internal const string ImageViewItemName = "ImageViewItem";
 		internal const string LabelViewItemName = "LabelViewItem";
@@ -57,7 +57,6 @@ namespace MonoDevelop.DesignerSupport.Toolbox
 		public event EventHandler DragBegin;
 		public event EventHandler<CGPoint> MenuOpened;
 		public event EventHandler ActivateSelectedItem;
-		public Action<NSEvent> MouseDownActivated { get; set; }
 
 		IPadWindow container;
 		NSTextField messageTextField;
@@ -256,11 +255,6 @@ namespace MonoDevelop.DesignerSupport.Toolbox
 
 		public override void MouseDown (NSEvent theEvent)
 		{
-			// MouseDownActivated needs to be called before logic activating toolbox item
-			// because MacToolbox uses this event to focus GTK widget that hosts MacToolboxWidget
-			// resulting into stealing focus from toolbox consumer that gains focus when toolbox item is activated
-			MouseDownActivated?.Invoke (theEvent);
-
 			collectionViewDelegate.IsLastSelectionFromMouseDown = true;
 			base.MouseDown (theEvent);
 			if (SelectedItem != null && theEvent.ClickCount > 1) {
diff --git a/main/src/addins/MonoDevelop.DesignerSupport/MonoDevelop.DesignerSupport.Toolbox/NativeViews/ClickedButton.cs b/main/src/addins/MonoDevelop.DesignerSupport/MonoDevelop.DesignerSupport.Toolbox/NativeViews/ClickedButton.cs
index 6ee0f8eb2a..bf9627a161 100644
--- a/main/src/addins/MonoDevelop.DesignerSupport/MonoDevelop.DesignerSupport.Toolbox/NativeViews/ClickedButton.cs
+++ b/main/src/addins/MonoDevelop.DesignerSupport/MonoDevelop.DesignerSupport.Toolbox/NativeViews/ClickedButton.cs
@@ -33,7 +33,7 @@ using MonoDevelop.Components.Mac;
 
 namespace MonoDevelop.DesignerSupport.Toolbox.NativeViews
 {
-	class ClickedButton : NSButton, INativeChildView
+	class ClickedButton : NSButton
 	{
 		public event EventHandler Focused;

 

@@ -54,30 +54,6 @@ namespace MonoDevelop.DesignerSupport.Toolbox.NativeViews
 			Focused?.Invoke (this, EventArgs.Empty);

 			return base.BecomeFirstResponder ();
 		}
-
-		#region INativeChildView

-
-		public void OnKeyPressed (object o, Gtk.KeyPressEventArgs ev)

-		{

-			if (ev.Event.State == Gdk.ModifierType.None && (ev.Event.Key == Gdk.Key.KP_Enter || ev.Event.Key == Gdk.Key.KP_Space)) {
-				PerformClick (this);
-			}

-		}

-

-		public void OnKeyReleased (object o, Gtk.KeyReleaseEventArgs ev)

-		{

-

-		}
-
-		public override void KeyDown (NSEvent theEvent)

-		{

-			base.KeyDown (theEvent);

-			if ((int)theEvent.ModifierFlags == (int)KeyModifierFlag.None && (theEvent.KeyCode == (int)KeyCodes.Enter || theEvent.KeyCode == (int)KeyCodes.Space)) {

-				PerformClick (this);

-			}

-		}
-
-		#endregion

 	}
 }
 #endif
\ No newline at end of file
diff --git a/main/src/addins/MonoDevelop.DesignerSupport/MonoDevelop.DesignerSupport.Toolbox/NativeViews/SearchTextField.cs b/main/src/addins/MonoDevelop.DesignerSupport/MonoDevelop.DesignerSupport.Toolbox/NativeViews/SearchTextField.cs
index 79c024f1e9..819eaaf109 100644
--- a/main/src/addins/MonoDevelop.DesignerSupport/MonoDevelop.DesignerSupport.Toolbox/NativeViews/SearchTextField.cs
+++ b/main/src/addins/MonoDevelop.DesignerSupport/MonoDevelop.DesignerSupport.Toolbox/NativeViews/SearchTextField.cs
@@ -32,7 +32,7 @@ using AppKit;
 
 namespace MonoDevelop.DesignerSupport.Toolbox.NativeViews
 {
-	class SearchTextField : NSSearchField, INativeChildView
+	class SearchTextField : NSSearchField
 	{
 		public event EventHandler Focused;
 
@@ -46,20 +46,6 @@ namespace MonoDevelop.DesignerSupport.Toolbox.NativeViews
 			Focused?.Invoke (this, EventArgs.Empty);
 			return base.BecomeFirstResponder ();
 		}
-
-		#region INativeChildView
-
-		public void OnKeyPressed (object o, Gtk.KeyPressEventArgs ev)
-		{
-
-		}
-
-		public void OnKeyReleased (object o, Gtk.KeyReleaseEventArgs ev)
-		{
-
-		}
-
-		#endregion
 	}
 }
 #endif
\ No newline at end of file
diff --git a/main/src/addins/MonoDevelop.DesignerSupport/MonoDevelop.DesignerSupport.Toolbox/NativeViews/ToggleButton.cs b/main/src/addins/MonoDevelop.DesignerSupport/MonoDevelop.DesignerSupport.Toolbox/NativeViews/ToggleButton.cs
index e9b56395fe..a215e42f6b 100644
--- a/main/src/addins/MonoDevelop.DesignerSupport/MonoDevelop.DesignerSupport.Toolbox/NativeViews/ToggleButton.cs
+++ b/main/src/addins/MonoDevelop.DesignerSupport/MonoDevelop.DesignerSupport.Toolbox/NativeViews/ToggleButton.cs
@@ -34,7 +34,7 @@ using MonoDevelop.Components.Mac;
 
 namespace MonoDevelop.DesignerSupport.Toolbox.NativeViews
 {
-	class ToggleButton : NSButton, INativeChildView
+	class ToggleButton : NSButton
 	{
 		public event EventHandler Focused;
 
@@ -69,22 +69,6 @@ namespace MonoDevelop.DesignerSupport.Toolbox.NativeViews
 				PerformClick (this);
 			}
 		}
-
-		#region INativeChildView
-
-		public void OnKeyPressed (object o, Gtk.KeyPressEventArgs ev)
-		{
-			if (ev.Event.State == Gdk.ModifierType.None && (ev.Event.Key == Gdk.Key.KP_Enter || ev.Event.Key == Gdk.Key.KP_Space)) {
-				PerformClick (this);
-			}
-		}
-
-		public void OnKeyReleased (object o, Gtk.KeyReleaseEventArgs ev)
-		{
-
-		}
-
-		#endregion
 	}
 }
 #endif
\ No newline at end of file
diff --git a/main/src/addins/MonoDevelop.DesignerSupport/MonoDevelop.DesignerSupport/ToolboxPad.cs b/main/src/addins/MonoDevelop.DesignerSupport/MonoDevelop.DesignerSupport/ToolboxPad.cs
index cf0bf27251..e649a96d36 100644
--- a/main/src/addins/MonoDevelop.DesignerSupport/MonoDevelop.DesignerSupport/ToolboxPad.cs
+++ b/main/src/addins/MonoDevelop.DesignerSupport/MonoDevelop.DesignerSupport/ToolboxPad.cs
@@ -55,21 +55,15 @@ namespace MonoDevelop.DesignerSupport
 #if MAC
 			this.window = window;
 			toolbox = new Toolbox.MacToolbox (DesignerSupport.Service.ToolboxService, window);
-			widget = GtkMacInterop.NSViewToGtkWidget (toolbox);
-			widget.CanFocus = true;
-			widget.Sensitive = true;
-			widget.KeyPressEvent += toolbox.OnKeyPressed;
-			widget.KeyReleaseEvent += toolbox.KeyReleased;
+			widget = new GtkNSViewHost (toolbox);
 
 			widget.DragDataGet += Widget_DragDataGet;
 			widget.DragBegin += Widget_DragBegin;
 			widget.DragEnd += Widget_DragEnd;
-			widget.Focused += Widget_Focused;
 
 			this.window.PadContentShown += Container_PadContentShown;
 			this.window.PadContentHidden += Container_PadContentHidden;
 
-			toolbox.ContentFocused += Toolbox_ContentFocused;
 			toolbox.DragSourceSet += Toolbox_DragSourceSet;
 			toolbox.DragBegin += Toolbox_DragBegin;
 		
@@ -92,11 +86,6 @@ namespace MonoDevelop.DesignerSupport
 			isDragging = false;
 		}
 
-		void Widget_Focused (object sender, EventArgs args)
-		{
-			toolbox.FocusSelectedView();
-		}
-
 		void Widget_DragBegin (object sender, DragBeginArgs args)
 		{
 			if (!isDragging) {
@@ -120,14 +109,6 @@ namespace MonoDevelop.DesignerSupport
 			}
 		}
 
-		void Toolbox_ContentFocused (object sender, EventArgs args)
-		{
-			if (!widget.HasFocus) {
-				widget.HasFocus = true;
-				toolbox.FocusSelectedView ();
-			}
-		}
-
 		void Toolbox_DragBegin (object sender, EventArgs args)
 		{
 			var selectedNode = toolbox.SelectedNode;
@@ -170,15 +151,11 @@ namespace MonoDevelop.DesignerSupport
 				widget.DragDataGet -= Widget_DragDataGet;
 				widget.DragBegin -= Widget_DragBegin;
 				widget.DragEnd -= Widget_DragEnd;
-				widget.Focused -= Widget_Focused;
-				widget.KeyPressEvent -= toolbox.OnKeyPressed;
-				widget.KeyReleaseEvent -= toolbox.KeyReleased;
 				widget.Destroy ();
 				widget.Dispose ();
 				widget = null;
 			}
 			if (toolbox != null) {
-				toolbox.ContentFocused -= Toolbox_ContentFocused;
 				toolbox.DragBegin -= Toolbox_DragBegin;
 				toolbox.DragSourceSet -= Toolbox_DragSourceSet;
 				toolbox.Dispose ();
diff --git a/main/src/core/MonoDevelop.Ide/MonoDevelop.Components.Docking/DockContainer.cs b/main/src/core/MonoDevelop.Ide/MonoDevelop.Components.Docking/DockContainer.cs
index 2dd13f38f1..00173c9d43 100644
--- a/main/src/core/MonoDevelop.Ide/MonoDevelop.Components.Docking/DockContainer.cs
+++ b/main/src/core/MonoDevelop.Ide/MonoDevelop.Components.Docking/DockContainer.cs
@@ -161,16 +161,18 @@ namespace MonoDevelop.Components.Docking
 
 		int usedSplitters;
 
+		const int SplitterSize = 5;
+
 		internal void AllocateSplitter (DockGroup grp, int index, Gdk.Rectangle a)
 		{
 			var s = splitters[usedSplitters++];
 			if (a.Height > a.Width) {
-				a.Width = 5;
-				a.X -= 2;
+				a.Width = SplitterSize;
+				a.X -= (int)(SplitterSize / 2);
 			}
 			else {
-				a.Height = 5;
-				a.Y -= 2;
+				a.Height = SplitterSize;
+				a.Y -= (int)(SplitterSize / 2);
 			}
 			s.SizeAllocate (a);
 			s.Init (grp, index);
diff --git a/main/src/core/MonoDevelop.Ide/MonoDevelop.Components.Docking/SplitterMacHostWidget.cs b/main/src/core/MonoDevelop.Ide/MonoDevelop.Components.Docking/SplitterMacHostWidget.cs
index f0859dea41..4f6cd550eb 100644
--- a/main/src/core/MonoDevelop.Ide/MonoDevelop.Components.Docking/SplitterMacHostWidget.cs
+++ b/main/src/core/MonoDevelop.Ide/MonoDevelop.Components.Docking/SplitterMacHostWidget.cs
@@ -42,7 +42,7 @@ namespace MonoDevelop.Components.Docking
 		public SplitterMacHostWidget ()
 		{
 			view = new MacSplitterWidget ();
-			host = new GtkNSViewHost (view, AppKit.NSWindowOrderingMode.Above);
+			host = new GtkNSViewHost (view);
 		}
 
 		public Widget Parent => host.Parent;
diff --git a/main/src/core/MonoDevelop.Ide/MonoDevelop.Components/HPanedThin.cs b/main/src/core/MonoDevelop.Ide/MonoDevelop.Components/HPanedThin.cs
index d7dce73991..8cfe8e8990 100644
--- a/main/src/core/MonoDevelop.Ide/MonoDevelop.Components/HPanedThin.cs
+++ b/main/src/core/MonoDevelop.Ide/MonoDevelop.Components/HPanedThin.cs
@@ -160,7 +160,7 @@ namespace MonoDevelop.Components
 			horizontal = parent is HPanedThin;
 
 			handle = new MacPanedHandleView (parent);
-			host = new Gtk.GtkNSViewHost (handle, NSWindowOrderingMode.Above);
+			host = new Gtk.GtkNSViewHost (handle);
 
 			GrabAreaSize = HandleGrabWidth;
 
diff --git a/main/src/core/MonoDevelop.Ide/MonoDevelop.Components/Mac/DragEventTrapView.cs b/main/src/core/MonoDevelop.Ide/MonoDevelop.Components/Mac/DragEventTrapView.cs
index f57f6fd6c5..ce2e77bf37 100644
--- a/main/src/core/MonoDevelop.Ide/MonoDevelop.Components/Mac/DragEventTrapView.cs
+++ b/main/src/core/MonoDevelop.Ide/MonoDevelop.Components/Mac/DragEventTrapView.cs
@@ -49,8 +49,11 @@ namespace MonoDevelop.Components.Mac
 	/// NOTE: this view should be added with NSWindowOrderingMode.Above to its superview, to
 	///       make sure the it's the first widget to receive pointer events.
 	/// </remarks>
-	abstract class DragEventTrapView : NSView
+	abstract class DragEventTrapView : NSView, Gtk.INSViewOrdering
 	{
+		const int DefaultSplitterZOrder = 1000;
+		public int ZOrder => DefaultSplitterZOrder;
+
 		NSCursor currentCursor;
 		bool hover, dragging;
 
@@ -99,6 +102,7 @@ namespace MonoDevelop.Components.Mac
 
 		public override void MouseEntered (NSEvent theEvent)
 		{
+			AddGdkEventFilter ();
 			lastEventTimestamp = theEvent.Timestamp;
 			if (!dragging) {
 				SetDragCursor ();
@@ -112,6 +116,7 @@ namespace MonoDevelop.Components.Mac
 			lastEventTimestamp = theEvent.Timestamp;
 			if (!dragging) {
 				SetDefaultCursor ();
+				RemoveGdkEventFilter ();
 			}
 			hover = false;
 			base.MouseExited (theEvent);
@@ -130,8 +135,6 @@ namespace MonoDevelop.Components.Mac
 		{
 			lastEventTimestamp = theEvent.Timestamp;
 			dragging = true;
-
-			AddGdkEventFilter ();
 		}
 
 		public override void MouseUp (NSEvent theEvent)
diff --git a/main/src/core/MonoDevelop.Ide/MonoDevelop.Components/Mac/GtkNSViewHost.cs b/main/src/core/MonoDevelop.Ide/MonoDevelop.Components/Mac/GtkNSViewHost.cs
index be3c2cdf5a..17999656f8 100644
--- a/main/src/core/MonoDevelop.Ide/MonoDevelop.Components/Mac/GtkNSViewHost.cs
+++ b/main/src/core/MonoDevelop.Ide/MonoDevelop.Components/Mac/GtkNSViewHost.cs
@@ -24,13 +24,25 @@ using System;
 using System.Diagnostics;
 using System.Runtime.CompilerServices;
 using System.Runtime.InteropServices;
-
 using AppKit;
 using CoreGraphics;
 using ObjCRuntime;
+using Foundation;
 
 namespace Gtk
 {
+	/// <summary>
+	/// This interface helps to reorganize the ZOrder of a native view inside a GdkQuarz window
+	/// </summary>
+	public interface INSViewOrdering
+	{
+		/// <summary>
+		/// This parameter is taking into account when this viewhost is added.
+		/// More values means the view is on top of others
+		/// </summary>
+		public int ZOrder { get; }
+	}
+
 	public sealed class GtkNSViewHost : Widget
 	{
 		const string LIBGTKQUARTZ = "libgtk-quartz-2.0.dylib";
@@ -67,7 +79,6 @@ namespace Gtk
 		NSView view;
 		NSView superview;
 		bool sizeAllocated;
-		NSWindowOrderingMode? zOrder;
 
 		public GtkNSViewHost (NSView view)
 		{
@@ -76,11 +87,6 @@ namespace Gtk
 			WidgetFlags |= WidgetFlags.NoWindow;
 		}
 
-		public GtkNSViewHost (NSView view, NSWindowOrderingMode position) : this (view)
-		{
-			zOrder = position;
-		}
-
 		void UpdateViewFrame ()
 		{
 			LogEnter ();
@@ -147,6 +153,20 @@ namespace Gtk
 			}
 		}
 
+		NSComparisonResult CompareViews (NSView view1, NSView view2)
+		{
+			if (view1 is INSViewOrdering viewOrdering1) {
+
+				if (view2 is INSViewOrdering viewOrdering2 && viewOrdering2.ZOrder >= viewOrdering1.ZOrder)
+					return NSComparisonResult.Ascending;
+				//view 1 on top
+				return NSComparisonResult.Descending;
+
+			}
+			//if view1 is not ordering view 2 on top
+			return NSComparisonResult.Ascending;
+		}
+
 		protected override void OnRealized ()
 		{
 			LogEnter ();
@@ -157,15 +177,12 @@ namespace Gtk
 					var superviewHandle = gdk_quartz_window_get_nsview (GdkWindow.Handle);
 					if (superviewHandle != IntPtr.Zero)
 						superview = Runtime.GetNSObject<NSView> (superviewHandle);
-				}
+					}
 
 				if (superview != null && view != null) {
-					if (zOrder.HasValue)
-						superview.AddSubview (view, zOrder.Value, null);
-					else
-						superview.AddSubview (view);
+					superview.AddSubview (view);
+					superview.SortSubviews (CompareViews);
 				}
-
 				base.OnRealized ();
 
 				UpdateViewFrame ();
diff --git a/main/src/core/MonoDevelop.Ide/MonoDevelop.Components/Mac/Messaging.cs b/main/src/core/MonoDevelop.Ide/MonoDevelop.Components/Mac/Messaging.cs
index fecd358c0f..a22c65271e 100644
--- a/main/src/core/MonoDevelop.Ide/MonoDevelop.Components/Mac/Messaging.cs
+++ b/main/src/core/MonoDevelop.Ide/MonoDevelop.Components/Mac/Messaging.cs
@@ -61,6 +61,9 @@ namespace MonoDevelop.Components.Mac
 
 		[DllImport (LIBOBJC_DYLIB, EntryPoint="objc_msgSend")]
 		public static extern uint UInt32_objc_msgSend (IntPtr receiver, IntPtr selector);
+
+		[DllImport (LIBOBJC_DYLIB, EntryPoint = "objc_msgSend")]
+		public extern static void void_objc_msgSend_IntPtr_IntPtr (IntPtr receiver, IntPtr selector, IntPtr arg1, IntPtr arg2);
 	}
 }
 #endif
diff --git a/main/src/core/MonoDevelop.Ide/MonoDevelop.Components/Mac/NSViewExtensions.cs b/main/src/core/MonoDevelop.Ide/MonoDevelop.Components/Mac/NSViewExtensions.cs
new file mode 100644
index 0000000000..9d7e89b4cc
--- /dev/null
+++ b/main/src/core/MonoDevelop.Ide/MonoDevelop.Components/Mac/NSViewExtensions.cs
@@ -0,0 +1,80 @@
+//
+// Author:
+//       Rolf Kvinge <rolf@xamarin.com>
+//
+// Copyright (c) Microsoft Corp. (https://www.microsoft.com)
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+
+using System;
+using System.Runtime.InteropServices;
+using Foundation;
+using ObjCRuntime;
+
+namespace AppKit
+{
+	public static class NSViewExtensions
+	{
+		delegate nint view_compare_func (IntPtr view1, IntPtr view2, IntPtr context);
+		static view_compare_func view_comparer = view_compare;
+
+		sealed class SortData
+		{
+			public Exception Exception;
+			public Func<NSView, NSView, NSComparisonResult> Comparer;
+		}
+
+		[MonoPInvokeCallback (typeof (view_compare_func))]
+		static nint view_compare (IntPtr view1, IntPtr view2, IntPtr context)
+		{
+			var data = (SortData)GCHandle.FromIntPtr (context).Target;
+			try {
+				var a = (NSView)Runtime.GetNSObject (view1);
+				var b = (NSView)Runtime.GetNSObject (view2);
+				return (nint)(long)data.Comparer (a, b);
+			} catch (Exception e) {
+				data.Exception = e;
+				return (nint)(long)NSComparisonResult.Same;
+			}
+		}
+
+		public static void SortSubviews (this NSView view, Func<NSView, NSView, NSComparisonResult> comparer)
+		{
+			if (comparer == null)
+				throw new ArgumentNullException (nameof (comparer));
+
+			var func = Marshal.GetFunctionPointerForDelegate (view_comparer);
+			var context = new SortData () { Comparer = comparer };
+			var handle = GCHandle.Alloc (context);
+			try {
+				SortSubviews (view, func, GCHandle.ToIntPtr (handle));
+				if (context.Exception != null)
+					throw new Exception ($"An exception occurred during sorting.", context.Exception);
+			} finally {
+				handle.Free ();
+			}
+		}
+
+		static readonly IntPtr sel_sortSubviewsUsingFunction_context_ = Selector.GetHandle ("sortSubviewsUsingFunction:context:");
+		static void SortSubviews (NSView view, IntPtr function_pointer, IntPtr context)
+		{
+			MonoDevelop.Components.Mac.Messaging.void_objc_msgSend_IntPtr_IntPtr (view.Handle, sel_sortSubviewsUsingFunction_context_, function_pointer, context);
+		}
+	}
+}
diff --git a/main/src/core/MonoDevelop.Ide/MonoDevelop.Ide.csproj b/main/src/core/MonoDevelop.Ide/MonoDevelop.Ide.csproj
index 35329ccb92..4314bb4e98 100644
--- a/main/src/core/MonoDevelop.Ide/MonoDevelop.Ide.csproj
+++ b/main/src/core/MonoDevelop.Ide/MonoDevelop.Ide.csproj
@@ -4252,6 +4252,7 @@
     <Compile Include="MonoDevelop.Components.Docking\SplitterMacHostWidget.cs" />
     <Compile Include="MonoDevelop.Components\Mac\DragEventTrapView.cs" />
     <Compile Include="MonoDevelop.Components\Mac\NativeToolkitHelper.cs" />
+    <Compile Include="MonoDevelop.Components\Mac\NSViewExtensions.cs" />
   </ItemGroup>
   <ItemGroup Condition="'$(Configuration)' == 'DebugMac' OR '$(Configuration)' == 'ReleaseMac'">
     <Compile Include="MonoDevelop.Components\Mac\KeyCodes.cs" />