Drop-down menus disappear within seconds
Recently (since installing Mavericks?) I am finding that drop-down menus disappear within a few seconds, or sometimes instantly.
This does NOT happen when I log on as a guest user.
It happens with both both mouse and trackpad.
I have tried a safeboot.
I have tried repairing permissions.
Any ideas please?
iMac, OS X Mountain Lion (10.8.5)