Sorry for bringing this old thread up.
The solution posted by driesena works but if the user continues doing further selections (in other fields) then the "Lock" condition avoids properly erasing these further selections.
In other words, I would also be interesed in finding a way to "block" a given selection, then further selections are done and pressing "Clear" would clear all selections except the blocked one.
Example: all sales team sharing the same document but depending on the user who opens the document, I want to block the field salesman to a given value. Then other selections (product group, year, month, ...) can be done but presing the clear button will clear all the selections except the one of the salesman.
Hi, Carlos. I answered a post similar to this a few weeks ago.
I wanted to keep a field locked even if a user uses 'unlock and clear'
Then, I made a second version, where I can let you apply this 'setting' using a macro (you could enable and disable this)
Hope it helps,