Be careful deleting Special Objects!

I've had a serious problem:

Suddenly I was not able to get into a ZMS Node any more. I got an error:

  Module Products.zms.zms, line 826, in updateVersion
  Module Products.zms.zmstrashcan, line 163, in run_garbage_collection
  Module Products.zms._globals, line 653, in daysBetween
  Module Products.zms._globals, line 646, in stripDateTime
IndexError: string index out of range

After messing around in _globals.py a little bit, I got the node running
again.
The thing, which had caused the problem was, that I experimented a lot
with special objects and deleted some of them again. But I overlooked,
that there where still some instances of them in the trash. These
zombies caused the error.

In previous versions ZMS took care of existing instances if you wanted
to delete a special object, even in trashcan. It seems that in
zms-2.11.0_27 there is a gap concerning this.

Regards
PeterZ, JKU