Adds the possibility to disable accessibility for TCustomTreeView

git-svn-id: trunk@35508 -

lcl/comctrls.pp

@@ -2719,6 +2719,7 @@ type
 
   TCustomTreeView = class(TCustomControl)
   private
+    FAccessibilityOn: Boolean;
     FBackgroundColor: TColor;
     FBottomItem: TTreeNode;
     FEditingItem: TTreeNode;
@@ -2918,6 +2919,10 @@ type
     // Accessibility
     function GetSelectedChildAccessibleObject: TLazAccessibleObject; override;
     function GetChildAccessibleObjectAtPos(APos: TPoint): TLazAccessibleObject; override;
+    // This property is provided when a tree view contains a huge amount of items,
+    // lets say 10.000+. In this case accessibility might slow the tree down, so turning
+    // it off might make things faster
+    property AccessibilityOn: Boolean read FAccessibilityOn write FAccessibilityOn default True;
   protected
     property AutoExpand: Boolean read GetAutoExpand write SetAutoExpand default False;
     property BorderStyle default bsSingle;

lcl/include/control.inc

@@ -118,7 +118,6 @@ begin
   if (WidgetsetClass <> nil) and (FHandle <> 0) then
     WidgetsetClass.DestroyHandle(Self);
   FreeAndNil(FChildrenSortedForDataObject);
-  FreeAndNil(FChildrenSortedForDataObject);
   inherited Destroy;
 end;
 

lcl/include/treeview.inc

@@ -2257,7 +2257,7 @@ begin
     if (FUpdateCount=0) and (Owner<>nil) then
       Owner.Invalidate;
     ok:=true;
-    if ok and (Owner<>nil) then
+    if ok and (Owner<>nil) and (Owner.AccessibilityOn) then
     begin
       lAccessibleObject := FOwner.GetAccessibleObject().AddChildAccessibleObject();
       lAccessibleObject.AccessibleDescription := 'Item';
@@ -3068,6 +3068,7 @@ begin
   // Accessibility
   AccessibleDescription := rsTTreeViewAccessibilityDescription;
   AccessibleRole := larTreeView;
+  FAccessibilityOn := True;
 end;
 
 destructor TCustomTreeView.Destroy;