Fixed issue JAM-Software#293 (OnAdvancedHeaderDraw is called with wrong PaintInfo.PaintRectangle)

Author: joachim.marder

Source/VirtualTrees.pas

@@ -10790,8 +10790,10 @@ procedure TVirtualTreeColumns.PaintHeader(TargetCanvas: TCanvas; R: TRect; const
 
     with TargetCanvas do
       begin
-      if hpeBackground in RequestedElements then
-        FHeader.Treeview.DoAdvancedHeaderDraw(PaintInfo, [hpeBackground])
+      if hpeBackground in RequestedElements then begin
+        PaintInfo.PaintRectangle := BackgroundRect;
+        FHeader.Treeview.DoAdvancedHeaderDraw(PaintInfo, [hpeBackground]);
+      end  
       else
       begin
         if tsUseThemes in FHeader.Treeview.FStates then