I didn't try your option because I don't have enough buttons on my mouse to make it work. All my other buttons have different functions assigned to them. It's very important to me that it work with a single button (and a single click + hold).
Thanks and let me know if you think I'm missing something.
I'm experiencing a conflict with one of my shortcuts. I have Command + Middle Mouse Button set up to search selection in Google and I use Button 3 to simulate the Command part of it (so Button 3 + Middle Mouse Button).
When the Google search is triggered, the Button 3 (mouse-up) event is not fired and my computer thinks I'm holding down the command key until I repress Button 3.
Uh sorry, that's a use case I haven't tried before. Probably it gets confused due to the various modifier / mouse states.
I think you could make it work by adding an additional cmd+middle mouse button that triggers on up, then send a cmd key up there. (And make the "search selected text with google" trigger on middle mouse down)