Title says it all, it would be nice to have that, either an optional toggle button (like play or record modes) in the edit (or mix) window, or through right click on the solo button!
Just a button for changing the solo mode (afl, pfl, sip) directly from the GUI.
right click on it and you get a context menu with:
or you can toggle through the modes with ctrl+click
the same way it works with the playback modes on the pb button (or record)...