Firefox contenteditable + flexbox column bug

This isn’t specifically about ProseMirror, but I encountered it in a ProseMirror-based editor and thought someone here might have an insight.

Firefox seems to lose track of the cursor’s column position when moving between elements styled with display: flex.

In this demo (a standard contenteditable div, containing flexbox sections), the cursor will jump to the end of the line when moving up and down between paragraphs in Firefox, but not in Chrome.

I haven’t yet found a report of this issue, or a suggested workaround.

Ugh, yeah, the intersection of contentEditable and modern CSS features is often poorly tested, or sometimes it even looks like no one thought about it at all. I recommend filing an issue on the Firefox bug tracker — those often sit for years with no activity, but sometimes they get picked up.

Still an issue in all versions of Firefox, tracking issue is here: