prettify = function (s) {
        s = s.replace(/-$/, 'minus'); // catch shortcuts using '-' key
        var keys = s.split('-');
        var k, i;
        for (i=0; i < keys.length; i++) {
            k = keys[i];
            if ( k.length == 1 ) {
                keys[i] = "<code><strong>" + k + "</strong></code>";
                continue; // leave individual keys lower-cased
            }
            if (k.indexOf(',') === -1){
                keys[i] = ( special_case[k] ? special_case[k] : k.charAt(0).toUpperCase() + k.slice(1) );
            }
            keys[i] = "<code><strong>" + keys[i] + "</strong></code>";
        }
        return keys.join('-');


    }
toggles display of keyboard shortcut dialog