I have been having problems for some time and have not found a solution on various forums. This problem is common with several applications but for this example I will use Entourage. I open the app and I select preferences and the window opens. If I then go to another space in spaces with the preferences open and then come back to the entourage space the preferences window has disappeared but I can see it for a split second or so when I come into the space. The only way I can get out of this is by pressing enter to accept the highlighted ok button to close preferences (note all menu options and the main entourage window are not accessible and the computer beeps & screen flashes when i click on the main window. I have tried showing all windows but the preferences pane is not there.