[Zope] Zope Management Interface: Bug of IE?? or Zope Feature

[Sven Hohage]

Hello,
in a hand-made ZClass the tabs of 2 of 4 instances show this-->>>>
<a href="manage_UndoForm" ----->>>>target="blank"  >
<span style="color: #000000;"><strong>Undo</strong></span></a>
This means the manage - view opens in a new window!
I can't reproduce my behaviour to find  a solution (the Classes have got an
attribute
target but can this mix up Zope??).
I use IE 6 (but 4.7 shows the same) on Win 2000 server.
Thanks!