Text/Markdown Editor App - Spell Check Support?

I have started using the Markdown editor app. (latest version in NextCloud 12.0.2) a lot recently and one “missing feature” seems to be spell checking. I have yet to find this essential feature, and the browser spell check doesn’t seem to be available in the edit window either (tried F.fox and Chromium on Ubuntu).
Is it really missing a spell-check, or is it just not obvious how to activate it?