Widget: Why Does ENTER Button Work on Simulator But Not on FR920XT?

I'm having a heck of a time figuring out why my widget buttons work fine in the simulator (specifying FR920XT) but don't work when I load my widget in an FR920XT.

I'm attempting to use the ENTER key for a very simple stop watch that uses ENTER to start, stop, and reset the timer time. I thought my problem might be because I'm attempting this as a widget, but I got the same behavior with running as an app.
I'm using onKeyPressed() and onKeyReleased() with an InputDelegate (since the API doesn't seem to trigger any behavior events for the ENTER key). Here's sample code (slightly simplified):

function onKeyPressed( evt ) {
if (evt.getKey() == Ui.KEY_ENTER) {
keyPressedTime = Time.now().value();
return true;
}
return false;
}

function onKeyReleased( evt ) {
if (evt.getKey() == Ui.KEY_ENTER) {
if ((Time.now().value() - keyPressedTime) >= 1) {
doReset();
} else {
doStartStop();
}
return true;
}
return false;
}

So what am I missing? I know it is possible to program the ENTER key at the top level of a widget--the ActivityIQ Weekly Step Summary widget does it.

Using Connect IQ Eclipse environment with Connect IQ 1.2.1 on Mac (10.10.5)