In ScrollWindowEx, if the window already has an update region then add

dlls/user/tests/win.c

@@ -2647,10 +2647,24 @@ void test_scrollvalidate( HWND parent)
             rcu.left,rcu.top,rcu.right,rcu.bottom);
     ReleaseDC( hwnd1, hdc);
 
+    /* test scrolling a window with an update region */
+    DestroyWindow( hwnd2);
+    ValidateRect( hwnd1, NULL);
+    SetRect( &rc, 40,40, 50,50);
+    InvalidateRect( hwnd1, &rc, 1);
+    GetClientRect( hwnd1, &rc);
+    cliprc=rc;
+    ScrollWindowEx( hwnd1, -10, 0, &rc, &cliprc, hrgn, &rcu,
+      SW_SCROLLCHILDREN | SW_INVALIDATE);
+    if (winetest_debug > 0) dump_region(hrgn);
+    exprgn = CreateRectRgn( 88,0,98,98);
+    tmprgn = CreateRectRgn( 30, 40, 50, 50);
+    CombineRgn( exprgn, exprgn, tmprgn, RGN_OR);
+    ok( EqualRgn( exprgn, hrgn), "wrong update region\n");
+
     /* now test ScrollWindowEx with a combination of
      * WS_CLIPCHILDREN style and SW_SCROLLCHILDREN flag */
     /* make hwnd2 the child of hwnd1 */
-    DestroyWindow( hwnd2);
     hwnd2 = CreateWindowExA(0, "static", NULL,
             WS_CHILD| WS_VISIBLE | WS_BORDER ,
             50, 50, 100, 100, hwnd1, 0, 0, NULL);

windows/scroll.c

@@ -77,6 +77,7 @@ INT WINAPI ScrollWindowEx( HWND hwnd, INT dx, INT dy,
     BOOL  bUpdate = (rcUpdate || hrgnUpdate || flags & (SW_INVALIDATE | SW_ERASE));
     int rdw_flags;
     HRGN  hrgnTemp;
+    HRGN  hrgnWinupd = 0;
     HDC   hDC;
     RECT  rc, cliprc;
     RECT caretrc;
@@ -125,15 +126,22 @@ INT WINAPI ScrollWindowEx( HWND hwnd, INT dx, INT dy,
                 RedrawWindow( hwnd, NULL, hrgnUpdate, rdw_flags);
         }
 
-        /* Take into account the fact that some damage may have occurred during
-         * the scroll */
+        /* If the windows has an update region, this must be
+         * scrolled as well. Keep a copy in hrgnWinupd 
+         * to be added to hrngUpdate at the end. */
         hrgnTemp = CreateRectRgn( 0, 0, 0, 0 );
         retVal = GetUpdateRgn( hwnd, hrgnTemp, FALSE );
         if (retVal != NULLREGION)
         {
             HRGN hrgnClip = CreateRectRgnIndirect(&cliprc);
+            if( !bOwnRgn) {
+                hrgnWinupd = CreateRectRgn( 0, 0, 0, 0);
+                CombineRgn( hrgnWinupd, hrgnTemp, 0, RGN_COPY);
+            }
             OffsetRgn( hrgnTemp, dx, dy );
             CombineRgn( hrgnTemp, hrgnTemp, hrgnClip, RGN_AND );
+            if( !bOwnRgn)
+                CombineRgn( hrgnWinupd, hrgnWinupd, hrgnTemp, RGN_OR );
             RedrawWindow( hwnd, NULL, hrgnTemp, rdw_flags);
             DeleteObject( hrgnClip );
         }
@@ -169,6 +177,11 @@ INT WINAPI ScrollWindowEx( HWND hwnd, INT dx, INT dy,
         RedrawWindow( hwnd, NULL, hrgnUpdate, rdw_flags |
                       ((flags & SW_SCROLLCHILDREN) ? RDW_ALLCHILDREN : 0 ) );
 
+    if( hrgnWinupd) { 
+        CombineRgn( hrgnUpdate, hrgnUpdate, hrgnWinupd, RGN_OR);
+        DeleteObject( hrgnWinupd);
+    }
+
     if( hwndCaret ) {
         SetCaretPos( caretrc.left + dx, caretrc.top + dy );
         ShowCaret(hwndCaret);