Steps to Reproduce

1. run the zul

   	<combobox width="150px" readonly="true" >
   			<comboitem label="A1" value="A1" />
   			<comboitem label="B1" value="B1" />
   			<comboitem label="C1" value="C1" />
   			<comboitem label="1A" value="1A" />
   			<comboitem label="2A" value="2A" />
   	</combobox>
   

2. click the drop-down arrow to open Comboitem list
3. press 1 on numbpad

Actual Result

Combobox selects the item "A1".

Expected Result

Combobox should select the item "1A".

Debug Information

In Combobox widget, otherPressed_(), String.fromCharCode(keyCode), keyCode of numpad 1 is 97 which is converted to char 'a'.

According to the conclusion of http://unixpapa.com/js/key.html

On keydown and keyup events, the keycodes are not character codes, and this conversion will give wild results for many keys. There is no general portable way to convert keycodes to characters

We should not convert keydown event's keycode into a string. The keypress event's which is suggested.
http://www.w3.org/2002/09/tests/keys.html demonstrates keycode difference.