Browsing Ido translation

we create a placeholder menuitem, to be used in case
* the menu is empty. this placeholder will stay around
* for the entire lifetime of the menu, and we just hide it
* when it's not used. we have to do this, and do it here,
* because we need a marker for the beginning of the recent
* items list, so that we can insert the new items at the
* right place when idly populating the menu in case the
* user appended or prepended custom menu items to the
* recent chooser menu widget.