When filtering by tags, I often want to remove one of the tags from a filter. I would like the "x" to appear when I hover over any of them, so it's easy to do this, without having to scroll down through a (huge!) list of tags to find the one that is enabled. Or let me put my cursor in there to delete it with the backspace key.
Or, even better, in the pull-down list, have the currently / recently selected tags listed first, so that I don't have to scroll through the huge list to disable / enable them:
How does is solve the user problems?
This would increase efficiency in bases having a lot of tags.