Registering two mouse buttons at once

URL of experiment:

Description of the problem: It seems that I can register the left and right buttons but once one button is pressed then the second doesn’t register. This can also confuse mouse.getPressed(). If I press left then right and then release left then right, getPressed gets stuck on left button down.

I’ve added a display of the getPressed array in the top right of my experiment.

Online I can’t check for the release of keyboard keys. Is there any way I can count the number of mouse buttons currently down?

In this thread I link to an example experiment that tracks buttons that released. Could that be of any help?