spellchecking within the codemirror is possible, I've made a proof of concept here: http://codemirror-spellcheck.tiddlyspot.com/
the question is if it's worth the work, because of the size of the dictionary which is around 1mb of size and stored in a single tiddler BTC -- You received this message because you are subscribed to the Google Groups "TiddlyWiki" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at https://groups.google.com/group/tiddlywiki. To view this discussion on the web visit https://groups.google.com/d/msgid/tiddlywiki/a06d35da-11b6-4cc5-841b-fa870cec4b76%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.

