Yeah, I've been with CW/Sonar for a while. I'm sure the marker could be probably re-mapped to the F11 key - I just haven't looked.
I've been working on older projects, so most of my marks are already establish. After that, I mainly use markings on the fly when I hear some sort of error/issue that I may want to come back and address later. When F11 quit working, it became very frustrating to hit stop on the transport, right click and insert a marking. First world problems, eh? lol.