So I know the editor has always worked this way, but I’m just throwing this out here for Epic’s consideration.
If you make a bunch of changes in a function and then switch to a different tab, you can start pressing undo/redo and outside of the popup that quickly fades, you can easily become lost about what it just did and where. I think you should reconsider the existing behavior and either force a flip back to the tab where the undo/redo operation took place, or have a separate undo stack for each function window. There have been times I know for sure I could have really used the latter.