My finder has been acting up recently. It started with the yellow minimize button disapearing. I couldn't minimize any windows, even by double clicking the top pane. Then, after awhile, the red close button didn't want to work na rin. had to close windows by quitting the apps. I tried repairing permissions and that seems to have solved the problem. Then, it started hapening to my wife's Macbook. I tried repairing permissions but this time, it did not work.
I get this all the time after a few days without a reboot, and counts as my #2 gripe against OS X (finicky Finder networking on SMB is #1). What I do is just force quit/relauch the Finder or just Log Out and In again. I just hope the Leopard Finder is not the old Finder in new iTunes clothes. Who cares about CoverFlowing documents if you can't even close your window, right?