As you want the source code to display the menu which will open when we hover the mouse.
Actually you did not need to put any code to achieve this. Simply just create a menu from the Appearance >> Menus. As I create a “Language” menu to set an example for you.
If you mean that the selected menu item have to shown at the top of the list then it is not possible. It is just a drop down menu which contain direct links and you expect the functionality similar to “select” and “options” tag. So the selected item will not be shown at the top of the wordpress menu list.
It requires customization and this is beyond our limitations and support policy.
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