Im positive that use base has nothing to do with this. However I cannot explain the behaviour. It is odd I agree. I believe it is something wierd in AutoLoader, DynaLoader or Tk's actual code.

I have tried to reproduce the behaviour using the things that Tk uses, but sofar to no avail. I would report this to Nick Ing-Simmons.

Updated

--- demerphq
my friends call me, usually because I'm late....