Bug when adding Register section to .ASPX page

Hi,
look at this image :

http://a.imageshack.us/img138/4053/bugattrregister.gif

I am adding a new .ascx control, that is located in an external assembly.

1) Resharper offers me to add the "Register" tag
2) The tag is looking like this
3) But as the .ascx control itself is placed in an external assembly
4) The page crushes with this error
5)The correct Register tag should containg the "Assembly" attribute


F.V.