I've found that going in and out of full screen mode is buggy when it comes to the behavior of an auto-hiding taskbar (one that pops up when you move your mouse to the bottom of the screen).
When I go into full screen mode, the auto-hide taskbar is disabled. This is reasonable enough of course. But when I come out of full screen mode, the taskbar is still disabled. I have to physically reduce the vertical size of the Sonar window in order to see the desktop at the bottom, before the taskbar will reappear.
Also, coming out of full screen mode does not revert the Sonar window back to its former size. It makes the screen maximized.