Hi

When drag and drop of files into a document library, files show as checked out.  How can we allow drag and drop of files without them automatically being tagged as checked out?

The usually means that you have required fields in the list. In other words, there's something that is required before the upload can be finalized.

You can turn off the checkout of documents during drag and drop, As Mike said above you are having required fields so make sure you remove them and disable the version settings.

http://social.msdn.microsoft.com/Forums/sharepoint/en-US/8cd88761-1c6f-4754-b4ec-fcf0235dcd2b/upload-multiple-documents-documents-are-with-status-check-out?forum=sharepointgeneralprevious 

check out is alreday disabled.

how to check wha are  required  fields?

The usually means that you have required fields in the list. In other words, there's something that is required before the upload can be finalized.

Edit the Properties of a document. The required fields will have an asterisk next to them.

Let's vote http://sharepoint.uservoice.com/forums/282887-customer-feedback-for-sharepoint-server/suggestions/7192842-enable-the-edit-properties-dialog-when-uploading-d

:)