Based on http://askubuntu.com/a/490326/7146 I determined that I don't need ibus-daemon, since I don't use multilingual input. I disabled it by switching System Setting > Language to none rather than ibus, and then restarting. Since then I have not suffered from slowdowns in the middle of application use. (Of course, this is not a suitable workaround for anyone who needs multilingual input.)
However, I still encounter a slowdown/hang on minimising/closing windows, as reported here https://bugs.launchpad.net/ubuntu/+source/xorg/+bug/1314587 -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1276186 Title: System becomes unresponsive, ibus-ui-daemon takes ~150 % cpu To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/ibus/+bug/1276186/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
