Search improvement request with tag browser

hi
would it be possible to add CTRL/SHIFT/ALT handling for the tag browser when an existing search request exists

example :
current behavior :
-search for "date:=today"
-now click in any way on a tag in the "tag browser" (example : click formats, then mobi)
=> result : "date:=today" is lost, now replaced by "formats:"=MOBI""

wished for behavior :
-search for "date:=today"
- CTRL click formats, then mobi
=> result : "date:=today AND formats:"=MOBI""

& ALT click could be "OR" instead of "AND" (or the reverse)

Thanks for reading.

edit: I'm aware you can create virtual libraries for the same result, it would just be a convenient way of making complex searches without having to type them out.