Problem with 'Detach Edge Verts' in Max7

[RichyC]

Hi all,
My first post so go easy on me!

I've suddenly got a problem after years of using max7 and its baffling and frustrating me...

I have created a model and I'm now in the process of unwrapping it. My problem is this - say you have 2 polys welded together, when i select the verts of one of them and click 'detach edge verts', it will make the other poly disappear in the Edit UVWs window. What used to happen before this problem arose was it would just seperate the 2 polys of course which is what i want to happen.

This problem arose yesterday when i accidentally pressed something in the Edit UVW window and now it will not revert back to how it used to be. I've tried closing and reopening max, rebooting my PC, I've tried rolling back to a previous save but its still remembering the problem that I have caused to occur. I can't see any options ticked/unticked that are out of the ordinary.

If that makes sense, can anyone help please? Has anyone else ever had this problem and managed to fix it?

Thanks in advance!