Hi Taajuus, I ran into the same problem and came up with what I think is a fix for the situation:
1. Go to your plugins directory and rename the plugin to my-optimized-dropdown-menus (I think this will prevent any updates from overwriting the changes you make).
2. Then in optimized-dm.php change Plugin Name to Plugin Name: My Optimized Dropdown Menus (again trying to prevent an update overwrite).
replace javascript in print_odm_javascript() at line 162 with:
<script type="text/javascript">
/* ref: https://gist.github.com/1918689 */
jQuery(document).ready(function($) {
var $widget = $('.odm-widget');
$('ul', $widget).each(function(){
var list = $(this);
var select = $(document.createElement('select'))
.attr('id',$(this).attr('id'))
.insertBefore($(this).hide())
.attr('onchange',
$widget.hasClass('odm-new-window')
? 'window.open(jQuery(\'#'+$(this).attr('id')+'\').val(), \'_blank\');'
: 'window.location.href=jQuery(\'#'+$(this).attr('id')+'\').val();');
$('>li a', this).each( function(){
option = $( document.createElement('option') )
.appendTo(select)
.val(this.href)
.html( $(this).html() );
});
list.remove();
});
});
</script>
3. Go into plugins and activate My Optimized Dropdown Menus and I believe that will do what you are looking for.
Seems to work for me, hope it works for you!