Jerud While I think this suggestion makes good conceptual sense, the two issues I have with it are:
I like to be able to see the whole filter at the top of the pane so at a glance I can tell what is being filtered. If the text filter is shown only as an icon not the full text and I have to click to view it, that would be a real productivity drain. Or more problematic, without the filter text in plain sight, I may think the filter text is set to one thing when in reality it is another and thus not realize that some items are being filtered out that shouldn’t based on what I am expecting the filter to be.
I still use the text filter (at least when it auto-expanded) for search because I strongly prefer to see my search results in the context of the outline and the existing search options (ctrl-F and ctrl-shift-F) do not do that and are not very useful for me. If the text filter were hidden in the popup panel, this would be very cumbersome.
Your comment about advanced mode made being a display setting is a good point that I hadn’t thought about, which is that, of course, the toolbar text filter can be used to contain advanced filters that can’t be represented by the icons and you can always clear the icons and just enter advanced text. The only difference is that it currently converts certain text to icons, which is annoying since I may be trying to type something more complex, such as with OR logic, and can’t because the auto-conversion kicks in before I’m done.
So now I think my preference would be to just leave it as it was before… no separate advanced mode. Rather just let the user decide if they want to use the text filter box for advanced filter terms. They can use the icons for AND terms or not, if they’d rather have all terms in the text filter. And keep the ? button to show how to construct an advanced search (maybe label the button “Advanced” instead of ?). This is so much simpler, and I think the auto-conversion between icons and advanced text is not really all that useful and sometimes confusing, and probably very difficult to get it to work for all possible cases.
If you are open to really thinking outside the current box… the way I have always thought it should work is that you should have a text input at the top of a pane which is a search box, meant for temporary filtering, with an icon at the end to activate a global search using the search box text, and then the text filter should be added to the end of the filter icons as text on a clickable button, not a text input, that when clicked would bring up a popup text input for editing the text filter (kind of like Jerud’s idea but showing the actual text not just an icon). With the new filter panel, the text input could be on that panel instead of a separate popup. While the text would be visible in the button and the panel input, at least there is just one place to input the filter text. And since you would not be using the text filter for searching, you would be changing it less often, if at all, so don’t need it as an input box in the toolbar.
In any approach, if you show the text filter on the toolbar, it seems your choice is to auto-expand the text input (or text button truncated by ellipsis) as much as possible to show as much as possible. Consider automatically moving it to a second line if the filter is too long (while the new text filter language is more verbose, I don’t think this is mandatory with the space that is available currently, but I can imagine others might need/want that).