The only missing feature that is being mentioned here is the "hidden buffers". Undo is working properly. A related comment on buffer management from the author

The only missing feature that is being mentioned here is the "hidden buffers". Undo is working properly. A related comment on buffer management from the author of the project: https://github.com/martanne/vis/issues/300#issuecomment-216034775 https://github.com/martanne/vis/issues/300#issuecomment-2160... I managed to live without hidden buffers so far, though I accept that they are convenient.