Hi Kirk,
I think we're confusing things by not defining terms better. When I say "Filter tab", I'm talking about a Contact Sheet tab with the name "Filter" on it. Something has to trigger that to happen and show "all" images. I don't think a "Filter tab" should just spontaneously be created without any user interaction unless the Filter tab is created from restoring the last session.
Does that make sense?
Right, that makes sense! Where I was talking about the filter tab in the catalog (left) pane, you were talking about the contact sheet… Yes, I now see I need to elaborate a lot on what would be nice (default) behaviour here…
Let's first separate both issues since I think the filter tab in the catalog (left) pane has only one issue: that it is empty when you start initially. Instead I think it should be showing the default (currently the rating) filter category, just as when you pressed new. Agree?
Now on to actually showing the filter results in a contact sheet. This is indeed tricky since, as you rightly say, it would be against what you'd expect if it where to show a filter contact sheet automatically when you e.g. click the left pane fillter tab or switch to catalog mode (in filter mode). So we'll need a trigger for actually executing the query and showing the result in a contact sheet.
Playing with things some more I actually noticed that the Clear button not only clears the query (like New) but also opens a contact sheet with the result (why doesn't new do that?). So here's a trigger, but not one we can use when you have implemented remembering the last filter; for that you'd also want a trigger that leaves the filter query completely intact.
It took me a while to see the difference between New and Clear; New really starts a new filter with the default first clause and clear leaves the filter clauses intact but simply removes any selected parts. Both obviously make sense. So basically you have what we need here. Except that I think “New” should also show the contact sheet. I guess that's easy to implement.
That clarified, I think all we need is a way to “execute” the initial query (be it the starting query or the remembered query from last session – once you have implemented that). Apart from adding another button, I don't see a logical way of creating this trigger from some other action. Not ideal, but we really need to be able to do this.
Extending this thought (i.e., a button to open the query in a filter contact sheet), are you ever planning on allowing multiple contact sheets with (different) filters? If so, then that button could also be used for that. Will add a lot of complexity to PLM though since you then (also) have to remember which filter contact sheet is showing which filter and switch filter settings when switching contact sheets. I can definitely see a use for this though (though, if you implement smart collections this would be much less important/unnecessary).
Hope what I say makes sense