997893 - nsMathMLContainerFrame interrupts reflow and causes an assert when a child is sticky positioned

Status: NEW

(Core :: Layout, defect)

Description

[:kip (Kearwood Gilbert)]

Attachment: asserting testcase with sticky inside MathML

nsMathMLContainerFrame::UpdateOverflow calls nsPresShell::FrameNeedsReflow and always returns false, which results in reflow being interrupted and failing an assertion when UpdateOverflow is called during reflow:

NS_ASSERTION(!mIsReflowing, "can't mark frame dirty during reflow");

This can occur when an nsMathMLContainerFrame's descendent is sticky positioned and an ancestor is the sticky scroll container.

Comment 1

[:kip (Kearwood Gilbert)]

This bug was identified while investigating Bug 926155.  More details are within the comments of Bug 926155.

Comment 2

[Corey Ford [:coyotebush]]

I think (as mentioned in bug 926155 comment 24) that the root problem involves incompatible assumptions about UpdateOverflow.