catch a key event in JFrame

hi,

i am coding a GUI application for some FSM(Finite State Machine) simulation purpose. the app can load the FSM and display it. i can selecte some part of FSM and using "delete" key to delete the selected states. i did register the KeyEventListener to the the JFrame. but when i try to press the "del" key the app doesn't do anything. after few tests, i think JFrame never listene to my key event. how can i make it possible to let the JFrame to listene to my "key event"?

Thanks~~~

[504 byte] By [BadCodera] at [2007-10-2 3:25:59]