Library:Filter Contains / Doesn't Contain`

Library:Filter*has only one box for placing search terms*.

I want *two boxes so that one can be "Contains" "Contains All",  and the
second box can be "Doesn't Contain"*

Furthermore, there is no drop down menu with either previous searches or
previous search terms.

Long winded complaint :

The current work-around (AFIK) is to create a smart collection. The
problem I have with smart collections is that it is tricky to reliably
create and later delete a smart collection.  LRC seems to have two types
of smart collections or smart collection folders, and I have struggled
to delete or edit a smart collection. Sometimes I double click on the
smart collection and LRC doesn't let me edit it - doesn't even open the
edit window. You seem to have put an invisible switch that causes
intermittent successes when attempting to edit.  I think you also have
two different context menus with smart collections, and I don't know
which one I am going to get.

Eliot Khuner
Berkeley CA