734273 - tab bar sometimes shows scroll arrows with only one tab after startup

Status: RESOLVED FIXED

(Firefox :: Tabbed Browser, defect)

Description

[Zac Luzader]

On startup the overflow scroll arrows are shown at either end of the tab bar, even though only one tab is shown. The tab bar will behave properly if enough tabs are opened (enough that would normally cause the arrows to appear) and then closed again.

Occurs in the 2012-03-08 Nightly, and on the m-c debug build for 2012-03-07. Does NOT occur in 2012-03-06 m-c debug. Occurs even in a blank profile.

Comment 1

[Alice0775 White]

Confirmed on
http://hg.mozilla.org/mozilla-central/rev/2f6368ca605e
Mozilla/5.0 (X11; Linux i686; rv:13.0) Gecko/20120308 Firefox/13.0a1 ID:20120308031058

Triggered by:
120c201a6644 Dão Gottwald — Bug 716334 - Avoid making the browser window visible before the layout is rendered. r=felip

Comment 2

[rob64rock]

I can confirm this bug on WinXP also, only after doing certain STR steps found here:
https://bugzilla.mozilla.org/show_bug.cgi?id=734311#c1

Comment 3

[Bill Gianopoulos [:WG9s]]

Also, it would seem to be a test for no scroll arrows showing with a single tab on a tier one platform, needs to be included in the test suite (since there obviously is not one).

Comment 4

[Dão Gottwald [:dao]]

Has this been reproduced with a clean profile?

Comment 5

[Bill Gianopoulos [:WG9s]]

This happens under Linux with a clean profile.

Comment 6

[Bill Gianopoulos [:WG9s]]

I also verified bug 716334 as the cause via backout.

Comment 7

[Dão Gottwald [:dao]]

Bug 644746 caused this, bug 716334 hid it.

Comment 8

[Dão Gottwald [:dao]]

I can only reproduce this when my startup cache is empty.

Comment 10

[Bill Gianopoulos [:WG9s]]

I have verified that backing out bug 644746 resolves this issue.

Comment 11

[Dão Gottwald [:dao]]

Attachment: patch

- delayed updateVisibility to the load event since the constructor runs earlier

- added _propagatedVisibilityOnce instead of unconditionally calling _propagateVisibility after calling updateVisibility for the first time, since this needlessly propagated the visibility twice in a row with browser.tabs.autoHide = false

- removed the syncUI call from TabsOnTop.init since updateVisibility takes care of this

https://tbpl.mozilla.org/?tree=Try&rev=2925420eb022

Comment 12

[Dão Gottwald [:dao]]

(In reply to Dão Gottwald [:dao] from comment #11)
> https://tbpl.mozilla.org/?tree=Try&rev=2925420eb022

Wrong rev, this is the right one: https://tbpl.mozilla.org/?tree=Try&rev=b1da36a46fa9

Comment 14

[:Felipe Gomes (needinfo for replies!)]

Comment on attachment 604652 [details] [diff] [review]
patch

Seems right to me, it looks simpler with these changes. It's a bit odd that the first time setting the visibility will do more work (propagate the value), but oh well..

Sadly all these layout timings are so tricky and cause of endless edge cases.. I hope we can eventually come up with a more robust solution

Comment 15

[Dão Gottwald [:dao]]

http://hg.mozilla.org/mozilla-central/rev/9688c946636f

Comment 17

[Dão Gottwald [:dao]]

Comment on attachment 604652 [details] [diff] [review]
patch

[Approval Request Comment]
We could back out bug 644746 instead of taking this patch, but I wouldn't consider that safer, given that tabbed browser code didn't stand still since then.

Comment 18

[Alex Keybl [:akeybl]]

Comment on attachment 604652 [details] [diff] [review]
patch

[Triage Comment]
Approved for Aurora 12 since this is a regression in 12 and the backout sounds like it may be riskier than a forward fix.

Comment 19

[Marco Bonardo [:mak]]

https://hg.mozilla.org/releases/mozilla-aurora/rev/9ba6560332ee

Comment 21

[Virgil Dicu [:virgil] [QA]]

Mozilla/5.0 (X11; Linux i686; rv:12.0) Gecko/20100101 Firefox/12.0
Mozilla/5.0 (Windows NT 5.1; rv:12.0) Gecko/20100101 Firefox/12.0

Verified in Firefox 12 beta4. No longer an issue on Ubuntu 11.10. Also doesn't occur on windows with the Stylesheet from comment 2.

Comment 22

[andy2011]

My Firefox 14.0a1 (2012-04-04) nightly still has this problem and have had it in every nighly for about the last 3 weeks

Every time I load it I have scroll arrows with only one or 2 tabs open and about 3 app tabs, also it doesn't fix itself when i overflow the tab bar and then close them i have had to put up with it this whole time and its becoming quite frustrating.

please see screenshot

http://tinyurl.com/cg25brh