[SLL] tab button gets stuck down when no keyboard plugged in?

[Ben Johnson]

Hey.

I'm running a new Linux based point of sale system at one of my sister's
coffee carts.  for the most part it's going pretty well, and I'm happy
about this.  :)  I run into a problem from time to time though.  one
weird problem happened this morning.  I wasn't present but the
description of the problem led me to believe that the tab button on the
keyboard had something sitting on it because keyboard focus was changing
very rapidly from one button to another.  The keyboard wasn't plugged in
though.  It had been plugged in earlier in the day and was unplugged
without rebooting the system.  could this be some weirdness with the
keyboard controller or the driver?  or...  can this be caused by
something else?  I can't afford to have silly problems like this disable
the system.  It's a GTK+ app, and as far as I know it doesn't do
anything with key-press events at all.

- Ben