With IE 11 found a case where click handler on a radio input behaves differently when delegated vs directly-bound.

// delegated click handler, works when clicked but not when using arrows.
$('#testform').on('click', '.radios', function( e ) {
     console.log('delegated click handler', $(this).val() );
});
//directly-bound click handler, always works even when using arrows
$('.radios').on('click', function( e ) {
    console.log('direct click handler', $(this).val() );
});

jquery version: 1.11.* and 2.1.3, most testing done with 1.11.3
works in browsers: Firefox: 38.0.1, IE 9 & 10, Opera 27.0.1689.66, Chrome 42.0.2311.15
does not work in: IE 11 Version: 11.0.9600.17801
OS: Windows 7 64-bit

Created a jsfiddle using jquery 1.11.0 at http://jsfiddle.net/damnmaudite/kt99moLf/24/
Note when actually clicking the radio option everything works, but when using arrows to select a value in IE-11 the delegated event is not triggered..