Fix T67008: Missing move handle and flickering in FileBrowser

Fix T67008: Missing move handle and flickering in FileBrowser

Allow split regions (child regions) to contribute to the action zones (azone) of the parent region.
This fixes the issues in file browser and also in the user preferences.

Reviewers: Severin, mont29, campbellbarton

Reviewed By: Severin, mont29, campbellbarton

Subscribers: brecht, campbellbarton

Maniphest Tasks: T67008

Differential Revision: https://developer.blender.org/D5273

1 files changed, 19 insertions, 1 deletions

diff --git a/source/blender/editors/screen/screen_ops.c b/source/blender/editors/screen/screen_ops.c
index 885cd1ee77d..72fec68070b 100644
--- a/source/blender/editors/screen/screen_ops.c
+++ b/source/blender/editors/screen/screen_ops.c
@@ -2458,6 +2458,15 @@ static int area_max_regionsize(ScrArea *sa, ARegion *scalear, AZEdge edge)
   return dist;
 }
 
+static bool is_split_edge(const int alignment, const AZEdge edge)
+{
+  return ((alignment == RGN_ALIGN_BOTTOM) && (edge == AE_TOP_TO_BOTTOMRIGHT)) ||
+         ((alignment == RGN_ALIGN_TOP) && (edge == AE_BOTTOM_TO_TOPLEFT)) ||
+         ((alignment == RGN_ALIGN_LEFT) && (edge == AE_RIGHT_TO_TOPLEFT)) ||
+         ((alignment == RGN_ALIGN_RIGHT) && (edge == AE_LEFT_TO_TOPRIGHT));
+
+}
+
 static int region_scale_invoke(bContext *C, wmOperator *op, const wmEvent *event)
 {
   sActionzoneData *sad = event->customdata;
@@ -2476,7 +2485,16 @@ static int region_scale_invoke(bContext *C, wmOperator *op, const wmEvent *event
     op->customdata = rmd;
 
     rmd->az = az;
-    rmd->ar = az->ar;
+    /* special case for region within region - this allows the scale of
+     * the parent region if the azone edge is not the edge splitting
+     * both regions */
+    if ((az->ar->alignment & RGN_SPLIT_PREV) && az->ar->prev &&
+        !is_split_edge(RGN_ALIGN_ENUM_FROM_MASK(az->ar->alignment), az->edge)) {
+      rmd->ar = az->ar->prev;
+    }
+    else {
+      rmd->ar = az->ar;
+    }
     rmd->sa = sad->sa1;
     rmd->edge = az->edge;
     rmd->origx = event->x;