user32: Invalidate button on WM_KILLFOCUS, like Windows does.

[Dmitry Timoshkov]

Tested with Spy++ under XP.

---
 dlls/user32/button.c |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)

diff --git a/dlls/user32/button.c b/dlls/user32/button.c
index f2097aa..926563c 100644
--- a/dlls/user32/button.c
+++ b/dlls/user32/button.c
@@ -446,6 +446,7 @@ static LRESULT ButtonWndProc_common(HWND hWnd, UINT uMsg,
         if (style & BS_NOTIFY)
             BUTTON_NOTIFY_PARENT(hWnd, BN_KILLFOCUS);
 
+        InvalidateRect( hWnd, NULL, FALSE );
         break;
 
     case WM_SYSCOLORCHANGE:
-- 
1.6.2.4