I can confirm this. After upgrading from Ubuntu 12.04 to 14.04 the font size (for the number of new emails) on the thunderbird icon in the unity launcher became extremely small.
$ uname -a Linux Dennis-PC 3.13.0-58-generic # 97-Ubuntu SMP Wed Jul 8 02:56:15 UTC 2015 x86_64 x86_64 x86_64 GNU/Linux Dennis -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1446007 Title: unity launcher fonts became extremely small after update To manage notifications about this bug go to: https://bugs.launchpad.net/unity/+bug/1446007/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs