Users only have one thumb
Just noticed that while looking at #86 (closed):
event17 - pressure: begin touch 0
event17 - pressure: begin touch 1
event17 - button state: touch 0 from BUTTON_STATE_NONE, event BUTTON_EVENT_IN_BOTTOM_R to BUTTON_STATE_BOTTOM
event17 - button state: touch 1 from BUTTON_STATE_NONE, event BUTTON_EVENT_IN_BOTTOM_M to BUTTON_STATE_BOTTOM
event17 - thumb state: touch 1, THUMB_STATE_MAYBE → THUMB_STATE_YES
event17 - thumb state: touch 0, THUMB_STATE_MAYBE → THUMB_STATE_YES
That's... unlikely. We should be able to say "no, two thumbs cannot exist" and be smarter about this.
This was a two-finger movement starting at the very bottom of the touchpad.
cc @mdmayfield, also ref #114 (closed)