SymptomsMac OS X Lion enables Full-Screen mode for some Mac OS X applications (Learn more).
Windows applications running in Parallels Desktop do not have a Full-Screen button in the upper right corner of the window:
CauseYou can use the OS X Lion Full-Screen feature with Windows programs running in Parallels Desktop, but there is no double-arrow icon in the upper-right corner of the program window as there is with Mac OS X applications.
ResolutionTo enter Full-Screen mode in a Windows program, from the Mac OS X menu bar choose View --> Enter Full Screen::
You can also use the key combination Control-Command-F.
To exit Full Screen mode, move the arrow to the top of the screen to show the menu bar, then click the double-arrow icon in the top right corner.