I have just bought an iMac 27" and configured it from my old iMac.
Everything seems to work well with the exception of an annoying automatic swipe to desktop screen from any program running in full screen.
Through three fingers swipe on the trackpad it is easy to go back to the full screen program.
For example running iPhoto and going to full screen and displying pictures, after a while it go to desktop.
It occurs also if I do not do anything after I go to full screen.
The same with ACDSee and other programs.
Can you help me?
I have solved the problem.
It was the Epson program Epudl that was running in the background (I do not know why) that seems to be incompatible with the new OS and causes continuous changes of full screen displays.
Once stopped and erased now the system works well.
Thanks a lot for your support