WinCE: Application level focus problem

Using Windows CE 6 and Qt 4.5.0 on a touch screen panel.

(Qt is built with the -D QT_NO_CURSOR option). I have a fullscreen main window with a few buttons and a QTreeView which I start as follows:

CPanel mainWindow;
::ShowCursor(FALSE); // hide Cursor
mainWindow.showFullScreen();

Then in CPanel I pop up a few different QDialog's in the following way:

CMessage* pDlgMessage = new CMessage(this);
ASSERT(pDlgMessage);
int nResult = pDlgMessage->exec();
delete pDlgMessage;

CMessage is a Dialog derived from QDialog.

When the dialog comes up, the Windows CE mouse cursor (which I have hidden at the start of the application) shows up.

The dialog works normally. When you quit the dialog, it disappears, but the full screen application kind of loses focus. When you hit a button now, nothing happens until it is hit a second time. As soon as you touch the screen after the dialog has quit, the Windows CE mouse cursor disappears again and the next time you touch a button, it works.