Your comments

This would be really useful for those of us with focus-follows-mouse window managers. We are used to moving the mouse over windows and type in stuff, but with ST layouts (such as 2 columns) I invariably end up typing in the wrong file. So I'm starting to use different ST windows instead of layouts, but it's less convenient.

A focus-follows-mouse option for layouts would be great.

Tried it, but it was almost as slow as Atom on my not-exactly-new machines and also chugged RAM for breakfast.

I'm giving up on ligatures for now, because ultimately having a fast and lean tool is more important than bells and whistles. But I hope they add it soon.