ActiveX Control stopped working in Delphi 2006

[mt02...@gmail.com]

An ActiveX control written in MFC works fine in Delphi 5, but when
switching to 2006 it stopped working.

The control is a simple one that use an MFC TreeCtrl and populates it
from a server. When using Spy++ I can see that the control indeed
populates as it should, and the WM_PAINT and WM_NCPAINT messages are
sent as well.
To exclude the possibility of if it being the control that is faulty I
ran an other instance - in parallell - in the ActiveX test container
and it works perfectly.

Has anybody got any idea what the problem could be? As of now I've run
out of ideas! I've (of course) googled for any related problems but
found none.

/Calle