WP8 : IExplorer 10 : on “keyup” event not firing for “RETURN” key

Question

I've just came across this interesting problem, or probably it's just me missing something very basic (hopefully). The problem is, that the keyup event is not firing for the return key in the WP8 browser, whereas all the other standard keys are firing this event up. I've tested this on the desktop, and IE10 is not having any issues with this, the event fires up nicely.

Can anyone else confirm that on their WP8 devices the keyup event is not being triggered for the "return" key ?

/using dojo syntax here/

 on(dom.byId("testinput1"), "keyup", function(evt){
    dom.byId("result1").innerHTML = "";
     if (evt.keyCode == keys.ENTER)
         dom.byId("result1").innerHTML = "ENTER pressed.";
});

Here is the jsfiddle link

• open it in IE10 -> no problem for both of the input boxes
• open it in WP8 browser (IE10) -> the first input box wont trigger keyup for the return key

Thanks for all your help.