Not time now, but will look into this change for a future release.

This begs the question: why show the choice at all? Shouldn't it always be on
for two button mice and off for three button ones?

After thinking about this I'm leaving it as is.  If you had a laptop with a 2
button builtin mouse, but plugged into a docking station with a 3 button button,
you'd want to be able to turn on emulation.  Depending on the order the 2 mice
were detected you may not have that option.