From ad8b5a310d3ba158f3c36aafd47d9b04722f3dd2 Mon Sep 17 00:00:00 2001
From: zeljko <zeljko@lazarus-ide.org>
Date: Mon, 12 Mar 2012 09:39:00 +0000
Subject: [PATCH] Qt: update cached FScrollY and FScrollX when value of
 scrollbar is changed.

git-svn-id: trunk@35900 -
---
 lcl/interfaces/qt/qtwidgets.pas | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/lcl/interfaces/qt/qtwidgets.pas b/lcl/interfaces/qt/qtwidgets.pas
index b132d1a8ee..074b521ff2 100644
--- a/lcl/interfaces/qt/qtwidgets.pas
+++ b/lcl/interfaces/qt/qtwidgets.pas
@@ -7239,7 +7239,8 @@ var
   b: Boolean;
 begin
   {$ifdef VerboseQt}
-  writeln('TQtAbstractSlider.SlotValueChanged() to value ',p1,' inUpdate ',inUpdate,' maxIs ',getMax);
+  writeln('TQtAbstractSlider.SlotValueChanged() to value ',p1,' inUpdate ',inUpdate,' maxIs ',getMax,
+  ' FChildOfComplexWidget ',FChildOfComplexWidget);
   {$endif}
 
   FillChar(LMScroll, SizeOf(LMScroll), #0);
@@ -7254,6 +7255,15 @@ begin
   LMScroll.Pos := p1;
   LMScroll.ScrollCode := SIF_POS;
 
+  if (FChildOfComplexWidget = ccwAbstractScrollArea) and Assigned(FOwner) and
+    (FOwner.ChildOfComplexWidget = ccwScrollingWinControl) then
+  begin
+    if LMScroll.Msg = LM_VSCROLL then
+      TQtCustomControl(FOwner).viewport.FScrollY := -p1
+    else
+      TQtCustomControl(FOwner).viewport.FScrollX := -p1;
+  end;
+
   if not InUpdate then
     DeliverMessage(LMScroll);