How can I hide the extra toolbar that appears above a message?

Hey, folks! Running TBird 102.0.3 (64-bit) on Windows. I'm wondering how I can hide (or at worst customize) the five-button toolbar that now appears on the right side above an opened message — Reply, Forward, Archive, Junk, Delete (see image). I already have those buttons on the main toolbar, so they're redundant. At least if I could add the option to file a message, I could use it, but I would prefer to hide it completely. Thanks for any help — and I'm comfy with diving into the config editor, if that's where the solution lies.