Dropdown menu with drop down menu (Sub drop down menu)

Hi,

I have made one folder and 10 pages in it. It is drop down header.

Now I need a drop down as 11 page and sub drop down page in it.

How can I add sub drop down within Folder/drop down menu?

You will need a custom plugin to achieve this

Or you can consider split dropdown to 2 or 3 columns. If you want to do this, I can give the code.