Bug 355886

Most of the time I'm using presets from my Favourite tag mapped to quick-choice menu, but sometimes I need one brush from other tag - so instead of making mess in tags (99% that I'd forgot to change things back after I'm done with the work), I just open the additional tag in the Brush Presets docker. Problem is: when I choose a brush from that additional tag, then change to some of my Fav, then I can't choose that additional one again, since it's still selected in docker (though the brush in fact is working in other preset chosen through quick menu). Only way then is activating some other preset from additional tag and then the preset I need. Worst case is when tag contains only one preset - it's impossible at all to chose it then!
Issue in general - there's always one preset chosen in the tag selected in Brush Presets docker, no matter what the actual brush settings are. So even when u choose some tag in the docker, u have one preset active, but u can't use it until u chose it again, which is impossible if there's no other preset in the tag.

Reproducible: Always

Steps to Reproduce:
1. Select some preset from Brush Presets docker.
2. Select some preset from quick menu (RMB for me).
3. U can't choose the preset from step 1 again, since it's still "active".
3a. Create some tag and assign only one preset to in.
3b. Choose the one-preset tag in Brush Presets docker - u can't activate this lone preset at all.

Actual Results:  
Unable to choose brush preset I need, since it's marked as "active" even though it's not.

Expected Results:  
Only the preset that is really in use should be marked as "active", every other should be available for activating.