On 2016-12-06 Tue 07:51 GMT-0800, Lars Ingebrigtsen wrote: > Eli Zaretskii writes: > >> If you change the condition to be true for any mode derived from >> message-mode, then all of them will inherit this feature. Are we sure >> those other modes all want that? For example, gnus-art.el defines one >> such mode; up until now, that mode didn't use this feature, maybe that >> was for a good reason? > > No, I don't think that was on purpose. I probably just didn't know > about derived-mode-p at the time... I've already proposed the one-line change in #25124. You can commit directly since this is just one line... I saw a comment "FIXME: use derived-mode-p" but I'm not sure why it wasn't changed directly on the code itself.