Feature request: "Passthrough with original modifiers" as option for .XCompose combinations

[mcclure]

I have been using WinCompose and like it a lot but I am struggling with what to use as my compose key. At first I did caps lock but I just couldn't train myself out of using caps lock for caps lock. Now I use the Windows key, but there's one Windows key shortcut I use all the time, WIN-SHIFT-S for screenshot.

Since compose-uppercase-S doesn't really compose with anything, what would be ideal is if I could just configure that one WIN-sequence, and no other, to be left alone as compose-uppercase-S. And I notice WinCompose has an existing method for configuring individual-key behaviors: .XCompose itself.

My proposal is that if instead of a "string", the .XCompose file has the unquoted word 'pass':

<Multi_key> <S> : pass # Screenshot

...then that keystroke gets re-injected to the OS with the windows key held down (IE, Windows experiences WIN-SHIFT-S being typed).

(I know C# but am not familiar with Windows internals, so I could potentially help with implementing this as a PR, but I would need some help with where in the code to look to get started.)