My customer list is in "flat" mode and cannot move customers, how do I ge out of "flat" mode?

The preference might have accidentally changed, patriciadavid.

You just need to right-click on the customer's list and select Hierarchical View. Then, click Yes to continue and get it back to how it they were listed before. 

Don't hesitate to tap on us again if you have other questions with QuickBooks. 

No, my chart of accounts is in flat mode.  What is that?

I'd be glad to provide you some information regarding the Flat Mode or View in your Chart of Accounts, dean8.

Flat Mode in QuickBooks Desktop means your sub-elements in the Chart of Accounts are listed with their parent accounts preceding the job name(s) separated by colons. See the sample screenshot below:

On the other hand, Hierarchical View means outlining your accounts and sub-elements nicely.

To switch between these views, you can click Account at the bottom and choose on how your Chart of Accounts will looks like.

You might find the following article interesting: How to organize your chart of accounts. It provides more details on how to manage your accounts as well as types of categories in QuickBooks Desktop.

Please update me on how it goes. I'll be around if you need further assistance with your concern or if you have any other questions in mind. I want to make sure I got you covered. Wishing you continued success!