I have a Dialog based app with PropertyPages on it without a PropertySheet. I change the pages using ShowWindow (SW_SHOW) and ShowWindow (SW_HIDE). All the PropertyPages are added to a collection that takes CPropertyPages and some other info. So when I create the page I get the PropertyPage from the collection and Create it. On some PropertyPages have a created a tabbed PropertySheet with with a couple of more PropertyPages. The problem is when I try to open a dialog or a MessageBox from those pages, it doesn't work. I hear the ding when the messagebox opens but my program freezes and I have to kill it using the taskmanager. Does anyone have any idea what it could be? I have tried setting different hWnd when I display the MessageBox but that doesn't seem to matter. It works fine when I open a MessageBox on the PropertyPage that is a child to my main window.