I'm experiencing this problem since 0.4.6 when I started using phex. It doesn't happen so offen since 0.5 but it's still there. I don't know the reason.
Before I had to restart phex. Now it repairs itself after some time (?). Sometimes it allows me to enter only one letter per click into form. And the after an hour or two everything works perfect again.

Real mystery...

I'm running Phex on Debian Linux with Blackdown Java 2 Runtime Enviroment.

J.