Dreamweaver freezes

Whenever I open a dialog box in Dreamweaver, i.e. Manage Sites, then open another window on my computer, Dreamweaver freezes up and I can't access the dialog box because it's hidden under the main window. The only thing I can do is to go to Task Manager and force DW to close. Then I have to reopen the app. Is there a way to keep DW from doing this?