Calibre crashes when ALT+TAB is used to switch to another application

[Bruno Girin]

When Calibre is running, using ALT-TAB to switch to another application results in Calibre crashing with a segmentation fault.

Steps to reproduce:
1. Open a terminal window
2. Start Calibre from the command line:
$ calibre
3. Press ALT-TAB to switch back to the terminal

Actual behaviour:
The Calibre window disappears and "Segmentation fault" is printed in the terminal window.

Expected behaviour:
Calibre doesn't crash.

Additional info: this does not happen when switching applications using the Unity side bar, only when using ALT-TAB.

ProblemType: Bug
DistroRelease: Ubuntu 11.10
Package: calibre 0.8.8+dfsg-1ubuntu1
ProcVersionSignature: Ubuntu 3.0.0-12.20-generic 3.0.4
Uname: Linux 3.0.0-12-generic x86_64
ApportVersion: 1.23-0ubuntu4
Architecture: amd64
Date: Sun Nov 20 19:57:05 2011
InstallationMedia: Ubuntu 11.10 "Oneiric Ocelot" - Beta amd64 (20110901)
PackageArchitecture: all
ProcEnviron:
 LANGUAGE=en_GB:en
 PATH=(custom, no user)
 LANG=en_GB.UTF-8
 SHELL=/bin/bash
SourcePackage: calibre
UpgradeStatus: Upgraded to oneiric on 2011-09-14 (66 days ago)