Using category system: Filtering the results by choosing more filters

[nji9]

Usecase:
In my large collection of cartoons I'm searching for a fitting one
for a special occasion.
I select the appropriate categories.
Say that there are still too much resulting cartoons.
After selecting all the results, the pane for "setting categories"
shows me (in italic) which other categories are set for the results.
So I can use them to restrict the results set.
Very good.
BUT beware!
If I choose one of this additional categories I MUST NOT do it
in the only pane where they are italic.
Because that would SET this category to all my result list.
(Which happened to my some times now; and no rewind button).

I have to look at the filter category pane and choose the
category there.
AND - best of all - at this filter pane the category is NOT italic.
THAT is really bad!
==> In the category filter pane those other categories should show
in italic too. As it is in the category set pane.

Moreover it seemed a good idea to me to show the numbers of files
that are set with a category (in parenthesis behind the category)
reflecting the selected (or resulting) filenames.
And not fix of all of them as it is now.