Logic Pro X keyboard command of the day. #LogicProX @StudioIntern1
Select Soloed Tracks 
Selects all tracks that are currently soloed. This can be very useful. At the minimum a quick way to be able to pan or level control the current group of playing tracks. Only available in the Edit>Select Tracks> menu, or by command. The command only works when the Arrange window is the current focus.
You can solo a track, silencing all tracks that are not also soloed. Soloing tracks is useful when you want to work on a track individually, or work on a few tracks, without hearing the other tracks in the project.
⇧ SHIFT – ⌃ CONTROL – ⌥ OPTION – ⌘ COMMAND