A variable indicating which window has focus (Arrange, MIDI editor, etc)

this would be very, very useful in scripts.

let's say you use a midi controller to trigger different REAPER actions, like many of us do with launchpads and other controllers. you could use this variable to make screen-dependent layouts to control different actions when different screens have focus. (scripts could check for the variable and transpose midi from the controller to a new swath of assigned actions -- leave that to the end users of course)

there are several actions assigned to my controller that aren't useful while in the MIDI editor, and i'd rather assign them to things like "select all notes on selected note row" etc.

A variable indicating which window has focus (Arrange, MIDI editor, etc)