USN-1463-2 fixed a bug in Unity 2D exposed by a recent Firefox update. It
was discovered that the issue was only partially fixed on Ubuntu 11.04.
When Thunderbird was started from the launcher, Thunderbird was still
unable to obtain pointer grabs under certain conditions. This update fixes
Original advisory details:
USN-1463-1 fixed vulnerabilities in Firefox. The Firefox update exposed a
bug in Unity 2D which resulted in Firefox being unable to obtain pointer
grabs in order to open popup menus. This update fixes the problem.