I know I should know better, but it's a while since I had to change my UltraEdit configuration. Vistaaaaagh! decided it would reset them for me.
I needed to re-add a couple of file associations and I forgot to add the leading "dot". UltraEdit silently fails and does not attempt the association. It appears to work (no error), but if you go back into the dialog, the added "extension" is not there.
If the dot is required syntax (which it is) then UE (and UES) should check for it and either require it or supply it if missing.
Oh and by the way, it seems Vistaaaaagh! will stop certain extensions being allocated to UE. I used to use ".wmm" under XP, but try as I might, I can't get this extension to be routed to UE so I ended up using a different one which works fine.
Hope this helps other unwary souls...
There is no such thing as an inconsistently correct system...
Therefore, aim for consistency; in the expectation of reaching correctness!