screen flicker when opening background windows

[Marius Gedminas]

After I upgraded to dapper I noticed that when I open a new Firefox window from xchat/gnome-terminal, the whole screen flickers in white briefly, and then a Firefox window appears in the background. It is as if Firefox appears on top of the original window, and is then quickly moved below.

This did not happen on breezy.

[psylence519 (psylence519)]

This is the same issue as #33913, and I imagine it will get rejected as well because this is a "feature" protecting you from the window you just purposefully opened.

[Sebastien Bacher (seb128)]

Thanks for your bug. Breezy already has that feature so it's probably not the issue. Do you open the URI by double click or with the context menu? Does it happen if you use an another browser?

[Marius Gedminas (mgedmin)]

I was not clear enough. I like the feature very much. I do not like screen flickering.

In breezy new windows used to appear in background, and IIRC I would see a flashing title in the task bar to tell me a new window appeared.

In dapper the same thing happens, but new windows momentarily flash in the foreground, and only then are moved into background.

This bug report is solely about the disconcerting flicker, so it is different from #33913.

[Sebastien Bacher (seb128)]

Do you still have that issue? Do you use xgl or something like that? Does anybody else has that issue?

[Marius Gedminas (mgedmin)]

I still have that issue. I do not use anything fancy (neither xgl, nor composite, nor EXA). I have a Radeon Mobility 7500, and I use the open-source driver, if that has any relevance.

[Carthik Sharma (carthik)]

I can reproduce this bug.

To reproduce:
1. Open gnome-terminal in fully maximized mode.
2. Type in either firefox <Return> or firefox &<Return>
3. Observe how you can see a white screen for a fraction of a second. If you try hard enough, you can also see the title bar that read "Mozilla Firefox".
4. Observe how Firefox is now in the background, behind gnome-terminal.

I never thought of this as a bug. Is it really a problem if firefox flashes for a brief amount of time (just once) before moving to the background? After all this produces no discomfort besides a milliseconds long white screen.

Thank you for reporting the bug.

[Daniel Holbach (dholbach)]

I can see a flicker (for nanoseconds) too. This is as things are. I don't see this as a bug, but as necessary drawing of X or GTK or whatever.

Firefox is not in the background for me. Please try again with recent Dapper.

[Marius Gedminas (mgedmin)]

I track Dapper and apt-get dist-upgrade daily. When I perform the sequence of steps detailed by Carthik Sharma I get the same result -- there's a brief flicker, and a new Firefox window opens in the background. (It might be different if I didn't have Firefox already running on another workspace, the smart focus stealing prevention code might position the window of a new Firefox instance on top. I haven't tried it -- new foreground windows are outside the scope of this bug.)

Once gain, I do not object to Firefox opening in the background. My Breezy used to open new Firefox windows in the background too. However there was no flicker at all when I was running breezy (just a new flashing taskbar icon for the new window).

I consider this to be a small regression: in breezy a new background window used to appear smoothly, while in dapper it briefly obscurs the foreground window.

[Sebastien Bacher (seb128)]

That's known upstream as pointed by Elijah: http://bugzilla.gnome.org/show_bug.cgi?id=332385, marking as confirmed according to that

[Sebastien Bacher (seb128)]

fixed upstream

[Sebastien Bacher (seb128)]

That upload fixes the issue:

 metacity (1:2.16.2-0ubuntu1) edgy; urgency=low
 .
   * New upstream version:
     - partial audit to fix timestamp usage (partly fixes #355180)
     - remove compilation warnings
     - automatic detection of stable/unstable in configure script
     - make windows be stacked correctly before showing them (Ubuntu: #33879)
     - use guint32 for timestamps (Ubuntu: #29584)