Hi Hillel
Yes thats what I have done and having got that far selected the existing Module from the other spec and at this point the warning appeared.
Now the file is opened in a new Tab for viewing but does not appear in the Spec Explorer listing. But when I save the original Module that references it I get the error attached. That it has not been imported. This is why I thought that the warning actually meant that you could not do this. (may be irrelevant but I am using a Mac)
thanks david