Any tricks to removing the antenna snap on winshield?

[minitrail]

figured I would ask before I force it and break something else.. the whole thing looks a little fragile (and maybe it is already broken) on my original windshield. I need to remove the glass to replace the gasket and do a little cleanup and repaint around the inside behind the dashpad.

I tried gentle pressure but it did not give and I am not sure if the plate it connects to is detached from the glass as well. Is there a preferred method for this?