This happens when the event in question is generated on non-top level (e.g. within ParseHTML), so it's not picked by InspectorTimelinePanel._innerAddRecordToTimeline, which only checks top-level records.
Created attachment 194846 [details]
Comment on attachment 194846 [details]
Is there a test for this?
Created attachment 195292 [details]
(In reply to comment #2)
> Is there a test for this?
Committed r147097: <http://trac.webkit.org/changeset/147097>