Give Nodes and Frames a Lock Icon

Currently when I delete all unused nodes with alt + x it does as it says. Even the connected but muted ones, also the ones I duplicated for later use. And sometimes I just want some of them to stay in place.

A lock icon like we have for keyframe graphs would be great to have for nodes and frames. So they are excluded from repositioning, deletion and/or value change. Something like this:

"CTRL + L" as a toggle maybe, and a lock tool / menu option, so that the unlocked status wouldn't have to have any icon at all.

Locked node colours could be a tad brighter or have a distinct outline.

and auto lock muted nodes