See testcase. The content never appears and the presshell keep on asserting about not being able to find an event frame.

Comment on attachment 255575 [details] Testcase Oops, I messed up the testcase. I'll post a new version sometime soon.

I messed up a bit when I was testing it out. Didn't realize my debugging alert was the cause of the bug :). (Incremental reflow bugs are wonderful...) document.width is way to trigger a reflow without bugging the user or having a body element. I think the initial reflow is bailing out because there isn't any content, so the frame constructor never get initialized.

In case it's useful, this is HTML only. (The equivalent XHTML testcase works just fine, although it does assert.)

See also discussion in bug 312858?

I don't think it's related; I'm pretty sure the issue here is that the frames can't be constructed under a null root rather than an issue with the correct content norifications. See PresShell::InitialReflow and nsCSSFrameConstructor::ContentInserted; if there isn't any root content, InitialReflow basically does nothing, and if there isn't a frame to put the root content into, ContentInserted does nothing, leading to no frames ever getting created.

is this related to bug 300540?

Definitely related; I'd almost call it a dup, except this has a distinct testcase.

Fixed by patch in bug 78070.