This shit has been bugging me for too long, so I went on a hunt and found a workaround.
The Symptoms are as follows:
- Clicking the address bar results in a 1-4 second delay
- Opening links in new tabs results in a 1-4 second delay
- +T results in a 1-4 second delay
PressAndHold[<pid>]: IMKServer Stall detected
is present in/var/log/system.log
at the time of the hang.
It appears to be to do with the PressAndHold helper - the thing that shows an IOS style selection of accents when you hold a key down.