Comment 1 for bug 438703

This will be documented in a user manual before I release it, but I haven't made it yet. The two ways to get to the keyboard screen are:

 1. Hit the "info" button
 2. A quad-tap on the mouse screen. Just tap with four fingers at once. It should be fairly robust at detecting quad-taps, so you shouldn't feel the need to be "precise" when it comes to ensuring all four fingers touch at the same time. I tend to actually "roll" my four fingers over the screen to activate it.

I feel that this is a reasonable resolution to the issue, but I wouldn't mind hearing if you still think that this should be handled differently. Please understand that I'm trying to make the mouse screen as bare as possible. I don't want people looking at their display as they try to use the mouse screen and then accidentally hit some button instead of performing a mouse event.