I am on Eclipse 2025-3 and the undo/redo only works using the right click context menu.

Keyboard shortcut, Edit->Redo/Undo and the Redo/Undo buttons in the toolbar do not work at all.

Changing history setting does fix the problem if I close all files in the workspace and re-open them.

I had this about a year ago and both times it appears to have started after a software upate to some of the installed apps.