Enharmonic changes by user should persist at least through the same measure.
When the user makes an enharmonic change, either on note entry or during later editing, I would like it to apply to all equivalent notes later in the same measure. After correspondence, Marc Sabatella said I could submit this, whether as an option or a default I don't know. It seems to me to apply to all forms of note input, but he may disagree. I usually make such choices when editing later, at which point I would have thought MuseScore wouldn't know how the notes were input.