I found solution for this bug. This patch seems to fix it and this bug: https://bugs.launchpad.net/ubuntu/+source/compiz/+bug/714909 too. The patch turns off any shadows enforced by config file and windows resizing on unfocusing. Let me know if it works and this is my first patch, so it might not work.
** Patch added: "metacity.patch" https://bugs.launchpad.net/ubuntu/+source/light-themes/+bug/769605/+attachment/2139957/+files/metacity.patch -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/769605 Title: light-themes make the system slow and laggy -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
