Update edges in UV map after editing mesh I was working on a mesh to create a new UV map for it. The UV unwrapping showed me some places in which the topology was awkward (tris in places that they could be quads), so I popped back over to edit mode, and fixed it by dissolving the bad edges and creating good ones. I neither created nor destroyed the existing vertices in this process.

Now my UV map has some rather large holes where there should be new edges. Is there a way to ask the UV editor to update where it has its edges placed?
The problem, I just found, was with the faces created by dissolving edges. Rather than create two new faces, it merged the entire strip into a single face. 

Suggestion for others with the same problem: Enter face select mode to make sure that new faces exist where you would expect them to.