The Options window/tab (ctrl+1) is sometimes a little "sticky" in the sense that it sticks itself to your cruiser and doesn't let go unless you dissable the window and try to manage drawing without it (HAH- sure), or restart oC. I've only noticed that this tends to happen when I have a tool like Pen selected and try to change the opacity.
Aside from that, Options and some of the other windows like to lock up on occasion, becoming completely unresponsive.
In both of these cases turning the window/tab on and off doesn't correct the problem. The only thing that seems to mend it is to completely restart oC. however, noting the frequency of this, having to restart so often really does make it annoying and break your creative flow.
Lastly, whenever I minimize the main window, all of the other windows such as Tools, Options, Layers, etc. stay up. The only way I can get them all to hide is by clicking the Hide All button in the bottom left corner of my screen. It's a bit of a hassle to hide all of my windows this way because it takes all other programs like firefox and terminal along with it. Having to click on these programs in the panel to bring them all back up simply to hide a few windows for oC isn't very efficient.
I'm running on Ubuntu Hardy with a Lenovo X61 wacom tablet laptop using crossOver Pro 7.1.0 and oC 4.5.15 Plus (100% legit copy).
If there's any other details needed, just let me know and I'll post them. ;)