Tree window does not always refresh immediately

[sdondley]

Using latest version of undotree on vim 9.

If I'm in an undotree, and I hit 'u' to undo, the tree window remains unchanged. I often have to hit 'u' again before a change is reflected. Same thing for ^r. See gif:

[mbbill]

Just updated my vim to 9.0 and experienced the exact same issue. I guess it might due to to some events not getting fired. Will dig a bit more into it later.

[9mm]

I also notice this in neovim latest. even when i tab over to the window it still doesnt show changes. i actually have to undo/redo on the left for them to show up