What's Something You Want to Learn How to Do in Your Code Editor?

I've had quite the tour of text editors in my career. And have settled on Emacs. Today, I sat down and wrote "What's Something You Want to Learn How to Do in Your Editor?" in my personal agenda.

Then I filled it out:

• I want to learn how to do multi-edit within a highlighted region
• I want to learn how to do undo within a highlighted region

(Both of these are possible in Emacs)

So I sat down and learned it, and along the way learned about the amazing: M-x narrow-to-region

But what about you. What's something you want to learn how to do?