1659940 - Iframe might not be notified the mouse leaving if restyle happens

Status: RESOLVED FIXED

(Core :: DOM: UI Events & Focus Handling, defect, P3)

Description

[Edgar Chen [:edgar]]

mLastOverFrame is used for notifying the sub-document the mouse out, it is a WeakFrame, so it could possibly be nulled-out after restyling and the sub-document won't be notified the mouse leaving.

Found this while working on bug 1653949, it adds new tests to test if the mouseenter/mouseleave event is fired properly while switching tab, but the test-verify on try will consistently get timeout due to the lack of mouseleave event on an iframe.

Comment 1

[Chris Peterson [:cpeterson]]

Edgar, does this new test failure happen in both Fission and non-Fission modes?

Comment 2

[Edgar Chen [:edgar]]

(In reply to Chris Peterson [:cpeterson] from comment #1)

Edgar, does this new test failure happen in both Fission and non-Fission modes?

Yes, it happens in non-Fission mode. And I think it is a long-existing behavior.

Comment 3

[Chris Peterson [:cpeterson]]

(In reply to Edgar Chen [:edgar] (PTO 08/21) from comment #2)

Yes, it happens in non-Fission mode. And I think it is a long-existing behavior.

Thanks. In that case, I'll clear the Fission flag.

Comment 4

[Edgar Chen [:edgar]]

Attachment: Bug 1659940 - Use mLastOverElement to notify the mouse leaving for an iframe;

mLastOverFrame is a WeakFrame, it could possibly be nulled-out, for example
after restyling, and the sub-document won't be able to be notified the mouse
leaving.

Comment 5

[Edgar Chen [:edgar]]

https://treeherder.mozilla.org/#/jobs?repo=try&revision=82cc9845f70c33204835edb339c0ae0352656afb

Comment 6

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/42b11b39afe4
Use mLastOverElement to notify the mouse leaving for an iframe; r=smaug

Comment 7

[Dorel Luca [:dluca]]

https://hg.mozilla.org/mozilla-central/rev/42b11b39afe4