“mouse1” is indeed the name of the event generated when you click on the left mouse button. But the mouse pointer does need to be within the graphics window when you click. I don’t know why “space” would work when “mouse1” does not.
If there’s any doubt as to the events you are generating, you can do this:
messenger.toggleVerbose()
this will set a mode where each message generated is printed to your console; it can be quite noisy. When I do it, and click on the left mouse button, I see this:
:08-19-2005 09:56:40 Messenger(debug): sent event: mouse1 sentArgs: []
:08-19-2005 09:56:40 Messenger(debug): sent event: time-mouse1 sentArgs: [1.3018960000000004]
:08-19-2005 09:56:40 Messenger(debug): sent event: mouse1-up sentArgs: []
:08-19-2005 09:56:40 Messenger(debug): sent event: time-mouse1-up sentArgs: [1.3442370000000003]