The difference between headings with spaces (== Foobar ==) and those without (==Foobar==) is minor but important. WikiEditor, VisualEditor and CodeMirror currently generate spaced headings using the menus or with keyboard shortcuts Ctrl + 1–6.
This proves an annoyance while editing and a problem while editing English Wiktionary, where the normalization guidelines mandates that mainspace entry headings be unspaced and triggers an abuse filter if not followed.
I request that a setting be added that when checked, makes the headings be created without spaces.