software-properties-gtk crashed with AttributeError in toggle_source_use(): 'NoneType' object has no attribute 'disabled'

[iGadget]

This might be a duplicate of #821467, but since mine happened under different circumstances, I thought it'd be wise to submit a new report. Feel free to mark this as a duplicate if I'm mistaken.

Mine happened shortly after starting up Thunderbird, right after a fresh boot of the system. This crash occured together with a crash of "oosplash.bin" (#835153), "bluetooth-applet", Unity and two instances of Compiz. I'll see if I can note the bug reports of those crashes to this one.

ProblemType: Crash
DistroRelease: Ubuntu 11.10
Package: software-properties-gtk 0.81.9
ProcVersionSignature: Ubuntu 3.0.0-9.14-generic 3.0.3
Uname: Linux 3.0.0-9-generic x86_64
Architecture: amd64
Date: Sun Aug 28 21:53:40 2011
ExecutablePath: /usr/bin/software-properties-gtk
InstallationMedia: Ubuntu 11.10 "Oneiric Ocelot" - Alpha amd64 (20110803.1)
InterpreterPath: /usr/bin/python2.7
PackageArchitecture: all
ProcCmdline: /usr/bin/python /usr/bin/software-properties-gtk -n -t 0
PythonArgs: ['/usr/bin/software-properties-gtk', '-n', '-t', '0']
SourcePackage: software-properties
Title: software-properties-gtk crashed with AttributeError in toggle_source_use(): 'NoneType' object has no attribute 'disabled'
UpgradeStatus: No upgrade log present (probably fresh install)
UserGroups: adm admin cdrom dialout lpadmin plugdev sambashare

[iGadget (igadget)]

Feel like I'm running in circles here, but it just happened again.

Related bugs (so far):
#838378
#838407
#835153
#838418

[iGadget (igadget)]

I figured it out:

Submitting a crashreport of "bluetooth-applet" (#838418) triggered a crash of
Unity (#838378 / #817352), submission of that crash triggered a crash of
Compiz (#838407), submission of that crash triggered a crash of
"oosplash.bin" (#835153), submission of that crash triggered a crash of "Software Sources" (#838417).

The above was reproducible (except for the bluetooth-applet crash) and started with a crash of all 5 components at the same time after a fresh boot when I had just started Thunderbird.

[Apport retracing service (apport)]

Thank you for taking the time to report this crash and helping to make Ubuntu better. This particular crash has already been reported and is a duplicate of bug #819350, so is being marked as such. Please look at the other bug report to see if there is any missing information that you can provide, or to see if there is a workaround for the bug. Additionally, any further discussion regarding the bug should occur in the other report. Please continue to report any other bugs you may find.