The document's content ended in an optional noteSection, so the content
match after the first child offered noteSection as its defaultType — and
that is what TipTap's clearNodes converts a block into. Every style command
on a top-level block past the first threw "Invalid content for node type
noteSection" and applied nothing. Spelling the same language as an
alternation puts a paragraph first again.
Steffen Becker
8b1bef9706