Selectmenu: call refresh(): this.menuItems was undefined

Calling refresh() on selectmenu without an option throw error: "this.menuItems is undefined"
Now i create this.menuItems also for selectmenu without option and in open function i check if this.menuItems realy has an item.

Fixes #10662
The `true` test is unnecessary as well. Really all you need is a single assertion that ensures that the length of `menuItems` is `0`. If there is a JavaScript error the test suite will fail.