delete "Open with" program for a file type

[NikNot]

Thanks for your help Mario.

Yup, Dapper. I right-click on the file (in this case one with some
.xyz suffix), then Open with. In the secondary menu I can see the
entry I created, but no matter what I do, there is no Remove option
associated with it. Can you pls describe the steps that led to that
"Remove".

Somewhat related: is there a way to use [Places]-[Search for files] to
search for a file in a hidden directory (.gnone2) - in this case, I
assume that if I found a file with the application name in it, I could
remove the entry by directly editing this file.

Nick