945367 - Need better heuristics at detecting 'root' scrollframe

Status: RESOLVED WONTFIX

(Core :: Graphics: Layers, defect)

Description

[Benoit Girard (:BenWa)]

Gaia apps like the settings app have some fixed position headers thus the primary scroll area is not the root element. We should adjust the heuristics to properly detect the primarily scrollable elements for these.

Comment 1

[Robert O'Callahan (:roc) (email my personal email if necessary)]

Yes, I agree. We could probably come up with something, like counting the number of overflow:auto/scroll scrollframes in the page and if there's only one, treat it as always active.

Comment 2

[Matt Woodrow (:mattwoodrow)]

We might want to also check that it covers some 'significant' portion of the page.

Comment 3

[Markus Stange [:mstange]]

With APZ on B2G we now have something similar: nsLayoutUtils::GetOrMaybeCreateDisplayPort (from bug 982141) gives a displayport to the first scrollable frame that's encountered during display list construction.

Comment 4

[Botond Ballo [:botond]]

Is there something we'd like to do here beyond what was already done in bug 982141?

Comment 5

[Benoit Girard (:BenWa)]

I don't remember if there was anything else to this bug then to bridge the gap until we got multi-APZ. I don't think there is. I think this is WONT FIX since we have a better alternative.