Small question on Key.ENTER handling

1 

// msg_box_txt is a TextField for user input
// by hitting ENTER, it sends msg_box_txt.text

var my_listener:Object = new Object();
my_listener.onKeyDown = function() {
	if (Key.getCode() == Key.ENTER) {
		//sends off msg_box_txt.text
		msg_box_txt.text = "";
	}
};
msg_box_txt.onSetFocus = function() {
	Key.addListener(my_listener);
};
msg_box_txt.onKillFocus = function() {
	Key.removeListener(my_listener);
};

msg_box_txt should be cleared, empty, after hitting ENTER. the problem that it contains one empty line, and the cursor is at beginning of the second line. how can this be fixed??