In Data Cleanup, in the completed goals list, when you click on a tile to see changes to words, there is an option to undo the change if the resulting word is in the frontier. If you "undo", then the only indication of the success is that the undo is no longer available.

It would be helpful to update the changes so that reverted changes are no longer listed (or listed as reverted), so the "undo unavailable" is only for changes that are no longer undoable because the resulting word has been otherwise changed.

(Should follow #2955.)