In full-screen mode, sometimes when I click around the
top of the screen, it registers a click on the Apple
menu bar instead. On one occassion, I noticed that a
couple of clicks near the top right of the screen
didn't register in the VNC window. Later, when I
escaped from full-screen mode, I found the clock on the
menu bar had been changed to analog, and the "Create
Network" dialog from the Airport menu had been opened.