I use a Kensington Expert Mouse so this may not work for you but you might be able to program a different mouse I dunno. My track ball has four click pads surrounding the actual ball. I just discovered that if I move my curser to the ‘bar’ line at the top of the project (to a position where I want to repeat something I’ve recorded) and right click on the top right hand click pad, the playback will stop as the playback curser returns to the position. AND, if I click the same pad again, the playback curser will release from pause and start playback again. And I can repeat this process forever if I want. It’s really handy to hear a section of the recording over and over, for example when you are showing a client (or yourself) where a trouble spot is.
Of course, if you just left click your mouse curser in the ‘bar’ area, (if the project is playing) the project will immediately return to this position and begin playback again from the curser’s position. The difference here is that (left click) you cannot pause the playback, nor can you initiate a ‘cold start’ playback, the project has to be playing. With the upper right click you can ‘cold start’ the project, pause it and begin playback. I think this is an awesome feature.