I need to hide a column of the detail table

You can do this in Edit Application > Permissions

For the field, choose NO for EDIT and DETAILS.

Or, for EDIT you can choose YES, BUT DISABLED if your goal is just to prevent the user from changing the value.
 
Nope. I looked more carefully at your example and what I've prescribed won't help. Sorry.

What you can do is the opposite of what I first recommended:

in Permissions, for the Grupo field/column set RESULT = NO, EDIT, CREATE, and DETAIL = YES. Of course, if your users use the main grid page for Categories, then Grupo will be missing from the Grid, but will show in the EDIT /CREATE pages.

A quick test just now seemed to work.

Sorry for the previous bad advice.
 
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