786476 - Background tabs cause multiple whole window repaints

Status: RESOLVED DUPLICATE of bug 786484

(Firefox :: Tabbed Browser, defect)

Description

[(dormant account)]

1.Turn on nglayout.debug.paint_flashing pref.
2. Load a page in a background tab
3. Observe foreground tab & rest of window repaint twice once page finishes loading. 

I guess this has something to do with tab reflows

Comment 1

[Timothy Nikkel (:tnikkel)]

I wasn't able to reproduce this on Linux, Windows XP, or Mac.

Comment 2

[(dormant account)]

(In reply to Timothy Nikkel (:tn) from comment #1)
> I wasn't able to reproduce this on Linux, Windows XP, or Mac.

Thanks for trying. I tried a build with a clean profile. It does not exhibit this behavior. I'm going to keep narrowing down differences between the two profiles until I figure this out.

Comment 3

[Timothy Nikkel (:tnikkel)]

We specifically kill invalidates that come from inside background tabs, so if this was happening it would be very interesting.

Comment 4

[(dormant account)]

Narrowed this down to browser.newtab.preload being set to true in my profile.

Comment 5

[:Gavin Sharp [email: [e-mail]]]

I can reproduce this on Mac. Setting the "busy" attribute on the tab is what causes the repaint - removing the attribute doesn't cause another repaint. This only happens if new tab preloading is enabled.

Theory: the hidden iframe in the window is causing us to unnecessarily repaint the whole window when certain chrome style changes occur.

Comment 6

[:Gavin Sharp [email: [e-mail]]]

The browser is inserted into browser-panel, and hidden by setting .collapsed = true:

http://hg.mozilla.org/mozilla-central/annotate/6e78c3efd115/browser/modules/BrowserNewTabPreloader.jsm#l88

Comment 7

[Dão Gottwald [:dao]]

(In reply to :Gavin Sharp (use [e-mail] for email) from comment #5)
> I can reproduce this on Mac. Setting the "busy" attribute on the tab is what
> causes the repaint - removing the attribute doesn't cause another repaint.
> This only happens if new tab preloading is enabled.
> 
> Theory: the hidden iframe in the window is causing us to unnecessarily
> repaint the whole window when certain chrome style changes occur.

So this is essentially a duplicate of bug 786484.