I've used my beloved Kinesis Advantage keyboard for over half a decade. Occasionally, I've had the issue that Eclipse stops responding to the F3 key for opening declarations. After checking all the key settings, I found that Eclipse was correctly configured. That lead me to use xev where I found that the F3 and F4 keys were behaving differently than the other function keys. Resetting the keyboard memory ( Program+Shift+F10 ) had no effect. Resetting it completely (holding F7 while plugging the keyboard in) also had no effect. Strange. Finally, I found the answer on the Kinesis FAQ . My F3 and F4 keys were behaving like multimedia keys (see manual to configure these). This feature can be disabled by holding = and pressing P for PC (you can also use W for Windows and M for Mac).