Tiny fail at undo: insert 1 before E, Ctlr+Z, move left/right: left editor moves around E, right editor moves around the nonexistent 1
And for real "action" there should be a delay/pause button to simulate conflicts like the ones described in the blog
Yes, the undo issue is a known bug in the website demo because it's messing with Lexical's undo functionality. It's not actually a DocNode bug. I'll fix it soon.
The feedback about the delay/pause button is also good, thanks!