[MlMt] key binding selector to toggle Preview pane?

[Shoshanna Green]

Is there a key binding selector to show and hide, or better yet toggle, 
the composer's Preview pane? I know there's a built-in keyboard command 
for this. But since I want the preview only when I'm actually using 
Markdown, I'd like to bind one key to simultaneously toggle both 
Markdown and the preview pane: both on, or both off.

If there's no key binding selector within MailMate for this, I can 
doubtless hack it with Keyboard Maestro (I mean, I'm pretty sure I can 
hack anything with Keyboard Maestro). But it would be cleaner and faster 
to do it within MailMate if possible. Thanks!

--
Shoshanna Green
shoshannag at gmail.com