regex in filter not working


Hi guys, I'm brand new to Mp3tag but it's clearly the power I've been looking for.
I've got a few questions and searching the forum didn't produce much.
I want to filter my view down to a specif folder named MP3. I only want to see mp3's in the root of that folder, not mp3's in subfolders.

From what I gather upon searching the forum is that I should be able to type a regex right in to the filter bar trigger by [F3]. I tried a few samples I found here such as .mp3$ but the view just goes blank acting as if it's taking that string literally. Is there a check box somewhere to get the filter input to accept regex's?



I'd just open the choose directory dialog via [Ctrl+D] and disable the subdirectories checkbox.