1151985 - [e10s] tab switching disconcerting because some state switches at different times than other state

Status: NEW

(Firefox :: Tabbed Browser, defect, P3)

Description

[David Baron :dbaron: (⌚️UTC-4, no longer working on Mozilla)]

This is a regression from about a week or two ago.  I suspect it is e10s-only, but I haven't verified that.

Switching tabs with the keyboard (Ctrl+PgUp / Ctrl+PgDn on Linux) has become very visually disconcerting, because some of the state switches immediately and (if the content process is busy) some of the state switches later.

In particular, I see immediate changes in:
 * the text in the window title
 * the scroll position of the tab bar (i.e., the tab bar scrolls horizontally to show the newly selected tab)
Yet the following state seems to wait for the content process for at least
a bit:
 * the styling of the selected tab (having a light background instead of dark)
 * the content

I think prior to this regression all of the things changed immediately, and if the content process was busy, a throbber immediately showed in the content process.

I think the most likely regression candidate is:
https://hg.mozilla.org/mozilla-central/rev/8194018355f6
but I haven't tested to see if it's in the right window.  (However,
I know the regression happened very close to another bug I filed with
the same regression candidate, bug 1148879; I just hadn't gotten around
to filing this one and was hoping somebody else would.)

Comment 1

[George Wright (:gw280) (needinfo me!)]

mconley and I discussed this when the original patch landed. We're still trying to work out what the "correct" thing to do here is. Mike pondered upon this here: https://bugzilla.mozilla.org/show_bug.cgi?id=1066531#c35

Does anyone have any input on how best we could approach this problem?

Comment 2

[George Wright (:gw280) (needinfo me!)]

Oops, I misread "update the title bar" as "update the URL bar". The things like the window title and so on should be relatively straightforward to fix, I think.

Comment 3

[Jeff Muizelaar [:jrmuizel]]

This is really annoying and makes it so that the visual idea of tab is ruined because it changes at different times. Shouldn't this have a milestone?

Comment 5

[Mike Conley (:mconley) (:⚙️)]

The good news is that this will probably be fixed once we get bug 1180916 fixed.

Comment 6

[Jim Mathies [:jimm]]

blocking bug is P2

Comment 7

[arni2033]

Should this block bug 1183135 or vice versa?

Comment 8

[Sylvestre Ledru [:Sylvestre]]

Moving to p3 because no activity for at least 1 year(s).
See https://github.com/mozilla/bug-handling/blob/master/policy/triage-bugzilla.md#how-do-you-triage for more information