From 257f95ec9771ca7cb313fa81ffa087bbaf4b819f Mon Sep 17 00:00:00 2001
From: juha <juha@lazarus-ide.org>
Date: Sat, 16 May 2020 08:23:09 +0000
Subject: [PATCH] LCL: Never trigger click events on TreeView's fold-arrow.
 Issue #37051, patch from CudaText man.

git-svn-id: trunk@63171 -
---
 lcl/comctrls.pp          |  5 +++--
 lcl/include/treeview.inc | 32 +++++++++++++++++++++++---------
 2 files changed, 26 insertions(+), 11 deletions(-)

diff --git a/lcl/comctrls.pp b/lcl/comctrls.pp
index 4516f79849..e96bff1871 100644
--- a/lcl/comctrls.pp
+++ b/lcl/comctrls.pp
@@ -3341,6 +3341,7 @@ type
     FMaxRight: integer; // maximum text width of all nodes (needed for horizontal scrolling)
     FMouseDownPos: TPoint;
     FMouseDownNodeSelected: Boolean;
+    FMouseDownOnFoldingSign: Boolean;
     FMultiSelectStyle: TMultiSelectStyle;
     FHotTrackColor: TColor;
     FDisabledFontColor: TColor;
@@ -3520,8 +3521,8 @@ type
     procedure CreateWnd; override;
     procedure Click; override;
     procedure DblClick; override;
-    //procedure TripleClick; override;  - Are these needed?
-    //procedure QuadClick; override;
+    procedure TripleClick; override;
+    procedure QuadClick; override;
     procedure Delete(Node: TTreeNode); virtual;
     procedure DestroyWnd; override;
     procedure DoCreateNodeClass(var NewNodeClass: TTreeNodeClass); virtual;
diff --git a/lcl/include/treeview.inc b/lcl/include/treeview.inc
index 7cebd42f1c..1fb5603641 100644
--- a/lcl/include/treeview.inc
+++ b/lcl/include/treeview.inc
@@ -3317,13 +3317,25 @@ end;
 
 procedure TCustomTreeView.Click;
 begin
-  if FMouseDownNodeSelected then
+  if not FMouseDownOnFoldingSign then
     inherited;
 end;
 
 procedure TCustomTreeView.DblClick;
 begin
-  if FMouseDownNodeSelected then
+  if not FMouseDownOnFoldingSign then
+    inherited;
+end;
+
+procedure TCustomTreeView.TripleClick;
+begin
+  if not FMouseDownOnFoldingSign then
+    inherited;
+end;
+
+procedure TCustomTreeView.QuadClick;
+begin
+  if not FMouseDownOnFoldingSign then
     inherited;
 end;
 
@@ -5566,7 +5578,7 @@ function TCustomTreeView.MouseDownNode(X, Y: Integer): TTreeNode;
 begin
   Result := GetNodeAt(X, Y);
   // Update the NodeSelected flag.
-  FMouseDownNodeSelected := (Result<>nil) and
+  FMouseDownNodeSelected := Assigned(Result) and
     (Result.Selected or ((tvoAllowMultiselect in Options) and Result.MultiSelected));
 end;
 
@@ -5608,18 +5620,20 @@ begin
   //CursorNode must be reassigned again - e.g. in OnMouseDown the node can be deleted or moved.
   CursorNode := MouseDownNode(X, Y);
 
+  //Flag is used for DblClick/TripleClick/QuadClick, so set it before testing ShiftState
+  FMouseDownOnFoldingSign :=
+    Assigned(CursorNode) and CursorNode.HasChildren and ShowButtons and
+    (LogicalX >= CursorNode.DisplayExpandSignLeft) and
+    (LogicalX < CursorNode.DisplayExpandSignRight);
+
   //change selection on left click
   if (Button = mbLeft) and//left click
      (([ssDouble, ssTriple, ssQuad] * Shift) = []) and//single or first of a multi click
      (CursorNode <> nil) then
   begin
-    if CursorNode.HasChildren and ShowButtons and
-       (LogicalX >= CursorNode.DisplayExpandSignLeft) and
-       (LogicalX < CursorNode.DisplayExpandSignRight) then
-    begin
+    if FMouseDownOnFoldingSign then
       // mousedown occured on expand sign -> expand/collapse
-      CursorNode.Expanded := not CursorNode.Expanded;
-    end
+      CursorNode.Expanded := not CursorNode.Expanded
     else if LogicalX >= CursorNode.DisplayStateIconLeft then
     begin
       // mousedown occured in text or icon -> select node and begin drag operation