I searched and searched. But could not find the answer for this.

I am in the Ledger of a checking account. And I am entering the payment made to Internet Service Provider. I want to enter the category as Expense : Communication : Internet. But neither Communication nor Internet are defined currently.

How do I create both -- Communication and Internet as its sub-category on the fly?

If you enter the transaction, KMM will ask you if you want to create the new category in a pop-up.