Jeff Muizelaar [:jrmuizel] Reporter
	Description • 8 years ago

It goes very fast from one side to the other. It is for example impossible to scroll by a single tab.

Ideally you could scroll the tab strip pixel by pixel just like other scrollable things.

	:Gijs (he/him)
	Comment 1 • 8 years ago

Is this a recent regression? I can't reproduce on beta...

	Markus Stange [:mstange] Assignee
	Comment 2 • 8 years ago

I can reproduce this on 45.0.1. It doesn't look like a regression to me.

	Jeff Muizelaar [:jrmuizel] Reporter
	Comment 3 • 8 years ago

Nope, we've had this problem for a long time.

	Mike Conley (:mconley) (:⚙️)
	Comment 4 • 8 years ago

The summary of this bug kinda ends on a cliffhanger. With what?

	Markus Stange [:mstange] Assignee
	Comment 5 • 8 years ago

Review commit: https://reviewboard.mozilla.org/r/45805/diff/#index_header
See other reviews: https://reviewboard.mozilla.org/r/45805/

	Markus Stange [:mstange] Assignee
	Comment 6 • 8 years ago

I don't think we gain anything from forcing scrolls to line up with the boundaries of the scrolled elements, for any type of scrollbox. I think we should allow pixel scrolling everywhere. There's one case where the decision maybe isn't completely clear, and that's menupopups: On OS X, if you have a native menu with lots of items so that it overflows, the native menu responds to touchpad scrolling by scrolling one item at a time. With this patch, in Firefox, overflowing menus will allow pixel scrolling. I think that's fine.

The patch treats wheel events with deltaMode DOM_DELTA_PAGE as line wheel events. I don't even know if there's a way to produce DOMSDELTA_PAGE wheel events.

	Neil Deakin
	Comment 7 • 8 years ago

Comment on attachment 8740492 [details]
MozReview Request: Bug 1263975 - XUL scrollbox (e.g. the tab bar) should respond to pixel scrolls by pixel scrolling. r?enndeakin

https://reviewboard.mozilla.org/r/45805/#review42967

	Pulsebot
	Comment 8 • 8 years ago

https://hg.mozilla.org/integration/mozilla-inbound/rev/954189d579d5

	Wes Kocher (:KWierso) (Not reading bugmail; email directly if needed)
	Comment 9 • 8 years ago

This broke some tests like https://treeherder.mozilla.org/logviewer.html#?job_id=25819438&repo=mozilla-inbound

Backed out in https://hg.mozilla.org/integration/mozilla-inbound/rev/b0628853f899

	Markus Stange [:mstange] Assignee
	Comment 10 • 8 years ago

Oops.

	Markus Stange [:mstange] Assignee
	Comment 11 • 8 years ago

The test was testing that we were ignoring the pixel delta and only using the lineOrPageDelta. We're no longer doing that.
This changes the test so that it doesn't really matter which delta is respected.

	Pulsebot
	Comment 12 • 8 years ago

https://hg.mozilla.org/integration/mozilla-inbound/rev/f46b25846856
https://hg.mozilla.org/integration/mozilla-inbound/rev/6963c6f6caac

	Carsten Book [:Tomcat]
	Comment 13 • 8 years ago
bugherder

https://hg.mozilla.org/mozilla-central/rev/f46b25846856
https://hg.mozilla.org/mozilla-central/rev/6963c6f6caac

	Avi Halachmi (:avih)
	Comment 14 • 8 years ago

Maybe not strictly a bug, but this broke two addons which allowed switching tabs by scrolling the mouse wheel over the tabs (Fire gestures and Tab Wheel Scroll).

	:Gijs (he/him)
	Comment 15 • 8 years ago

(In reply to Avi Halachmi (:avih) from comment #14)
> Maybe not strictly a bug, but this broke two addons which allowed switching
> tabs by scrolling the mouse wheel over the tabs (Fire gestures and Tab Wheel
> Scroll).

Please file a followup bug with more details about what broke and ping the assignee of this bug there if there's an API issue?

	Avi Halachmi (:avih)
	Comment 16 • 8 years ago

I won't file a bug since I don't know if it's a bug. If Markus thinks it's a bug, he can file it.