Closed Bug 1336519 Opened 3 years ago Closed 3 years ago
[APZ] Wrong layerization (and missing content) with background-attachment:fixed
This is a regression from bug 1298218. Steps to reproduce: 1. Load the testcase. 2. Scroll down until the blue bar is just offscreen. 3. Hover the scrollbar in order to trigger a main thread paint. 4. Scroll up. The blue bar should become visible. But it's not visible, because FrameLayerBuilder merged it into a layer below the fixed layer, because it thought the fixed layer was clipped by a scrolled clip the size of the viewport.
Assignee: nobody → mstange
Status: NEW → ASSIGNED
Comment on attachment 8833373 [details] testcase The bug doesn't happen with position:fixed.
Attachment #8833373 - Attachment is obsolete: true
Summary: [APZ] Wrong layerization (and missing content) with background-attachment:fixed / position:fixed → [APZ] Wrong layerization (and missing content) with background-attachment:fixed
Comment on attachment 8833380 [details] Bug 1336519 - Don't try to detect scrolled clips using AGRs in non-APZ mode. https://reviewboard.mozilla.org/r/109626/#review112200
Attachment #8833380 - Flags: review?(matt.woodrow) → review+
BTW, I believe I'm hitting this bug on the Mozilla phonebook (which has background-attachment:fixed on its <html> node). STR: 1. Visit https://phonebook.mozilla.org/?search/a (or probably any other long phonebook search-results page) 2. Hit your "End" key. 3. Scroll back up the page, with mousewheel scrolling or two-finger scrolling on trackpad (not arrow-keys or pageup). ACTUAL RESULTS: As you scrollback up, the top part of your viewport doesn't repaint right away as (particularly bits of newly-visible cards). It sometimes just stays blank indefinitely, until you force a repaint by switching windows/tabs/etc. The regression range includes bug 1298218's changes, which is why I'm pretty sure it's this bug (a background-attachment:fixed regression from bug 1298218).
Pushed by email@example.com: https://hg.mozilla.org/integration/autoland/rev/7796783a9de9 Don't try to detect scrolled clips using AGRs in non-APZ mode. r=mattwoodrow
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