Represents a dropdown menu.
| AppendAction | Adds an item that executes an action in the dropdown menu. | 
| AppendHeaderAction | Adds a header item to the dropdown menu. | 
| AppendSeparator | Adds a separator line in the menu. | 
| ClearHeaderItems | Clears all header items from the menu. | 
| ClearItems | Clears all items from the menu. | 
| InsertAction | Adds an item that executes an action in the dropdown menu. | 
| InsertHeaderAction | Adds a header item to the dropdown menu. | 
| InsertSeparator | Adds a separator line in the menu. | 
| MenuItems | Gets the list of menu items. | 
| PrepareForDisplay | Gets the status of all items by calling their status callback and removes the excess separators. | 
| RemoveHeaderItemAt | Removes the menu header item at index. | 
| RemoveItemAt | Removes the menu item at index. |