Update-notifier window invisible in utopic

[Nick Moffitt]

Somehow I ended up with update-notifier not being visible on my utopic laptop. I can see it in the dock on the left, and I can interact with it that way (right-clicking to choose "install available software"), and I can even close it out from there. But I cannot cause its main window to appear on any desktop.

Rebooting does not clear this problem, and it happens even with the reboot notifications.

ProblemType: Bug
DistroRelease: Ubuntu 14.10
Package: update-notifier 3.157
ProcVersionSignature: Ubuntu 3.16.0-24.32-generic 3.16.4
Uname: Linux 3.16.0-24-generic x86_64
ApportVersion: 2.14.7-0ubuntu8
Architecture: amd64
CurrentDesktop: Unity
Date: Wed Nov 5 08:48:20 2014
InstallationDate: Installed on 2014-05-29 (159 days ago)
InstallationMedia: Ubuntu 14.04 LTS "Trusty Tahr" - Release amd64 (20140417)
SourcePackage: update-notifier
UpgradeStatus: Upgraded to utopic on 2014-10-24 (11 days ago)

[Steve Langasek (vorlon)]

I have seen this problem here as well. As the code in update-notifier hasn't changed, I think this is probably a bug in unity, refusing to display the window.

[Nick Moffitt (nick-moffitt)]

A second restart did clear it, so it may be a race in some kind of display layer management somewhere, or something to that effect.

[Marco Trevisan (Treviño) (3v1n0)]

I don't think this is much related to unity, since I experienced this also in older versions of ubuntu (this problem has always been there ihmo).

When the window is minimized, sometimes doesn't get mapped again, and this is not possible also using other window managers (or tool such as libwnck).