I've got a strange problem. Some of my objects are stretching in one direction when I just want to rotate them.

See this screenshot:



How those objects were created:
split some polys, extract them, extruded them to give them a little thickness.

I deleted the history on them and freezed the transformation.

What elese can I do? I just want to be able to rotate them without affection their proporions. All other objects rotate fine.