It would appear the APZC has no axis lock, making it very hard to scroll vertically when a page has horizontal scrolling (for example, after you've zoomed in slightly). I think we should mimic the Android JPZC behaviour here.

We have axis locking implemented (bug 892684), but it's off by default. It can be turned on using the "apz.axis_lock_mode" preference (see http://dxr.mozilla.org/mozilla-central/source/modules/libpref/src/init/all.js?from=all.js#324).

(In reply to Botond Ballo [:botond] from comment #1) > We have axis locking implemented (bug 892684), but it's off by default. It > can be turned on using the "apz.axis_lock_mode" preference (see > http://dxr.mozilla.org/mozilla-central/source/modules/libpref/src/init/all. > js?from=all.js#324). Well that's an interesting choice. I guess we can use this bug to track turning it on?

(In reply to Chris Lord [:cwiiis] from comment #2) > (In reply to Botond Ballo [:botond] from comment #1) > > We have axis locking implemented (bug 892684), but it's off by default. It > > can be turned on using the "apz.axis_lock_mode" preference (see > > http://dxr.mozilla.org/mozilla-central/source/modules/libpref/src/init/all. > > js?from=all.js#324). > > Well that's an interesting choice. Kats said in https://bugzilla.mozilla.org/show_bug.cgi?id=892684#c11 that "with axis locking turned on it's pretty hard to do a pan that's not axis-locked, so that might need some tuning but we can do that if/when we turn it on on B2G by default." I'm not sure whether there is anything besides that tuning holding this up from being turned on by default. > I guess we can use this bug to track turning it on? Sure.

Using the "sticky" mode (apzc.axis_lock_mode = 2) helps avoid problems caused by unintended locking. This is the mode we used in Firefox for Metro.

Comment on attachment 8397970 [details] [diff] [review] Switch to sticky axis locking Review of attachment 8397970 [details] [diff] [review]: ----------------------------------------------------------------- LGTM, do we want to uplift this to Aurora too?

Maybe. Let's let it bake a bit on m-c first.

Comment on attachment 8397970 [details] [diff] [review] Switch to sticky axis locking [Approval Request Comment] Bug caused by (feature/regressing bug #): none User impact if declined: very easy to scroll on the secondary axis even when not desired. this also results in more painting which is bad for performance Testing completed (on m-c, etc.): on m-c Risk to taking this patch (and alternatives if risky): low risk, affects b2g only. String or IDL/UUID changes made by this patch: none