Or you can just do the equivalent of quitting the process in Task Manager in Windows, and quit the process in Activity Monitor. I believe it may be listed within there by user name, beyond that it should be obvious. Somewhat more user-friendly, no?
you CAN get 100% colour bars in FCP, just go to the generator and select ‘more bars and signals’. There is a drop-down menu in the controls tab in the viewer, I believe, and you can select 100& bars there.