see screenshot below

Seems like the RTF control takes a default margin of about 1mm when you set it to 0
The text control doesn't do that. I really need to have the textbox and rtf textbox aligned the same.
This screenshot is made from wpf 2010.3. The margins set to zero in version 2009.2 worked just fine.
Any ideas? Setting a negative margin doesn't work.
Joris