- DWORD dwStyle = ::GetWindowLong(hwndClient, GWL_STYLE);
- DWORD dwThisStyle = ::GetWindowLong(GetHwnd(), GWL_STYLE);
+ DWORD dwStyle = ::GetWindowLong(hwndClient, GWL_EXSTYLE);
+
+ // we want to test whether there is a maximized child, so just set
+ // dwThisStyle to 0 if there is no child at all
+ DWORD dwThisStyle = pChild
+ ? ::GetWindowLong(GetWinHwnd(pChild), GWL_STYLE) : 0;