What is this mysterious floating menu bar?
I had similar problems with applications leaving artefacts on the screen with later versions of OS X. Try to quit also apps in menubar. Download something like magican, or some other program that lets you see what all is running on your mac, check activity monitor for what all is running. 

And it may be good to try to relaunch finder (cmd+option+esc, and choose finder, relaunch).