Outlook drag and drop with public folders.

Hello,

I've had a couple users point out since our migration from exchange 2010 to 2013 public folders that the drag and drop between the folders has changed. 

Exchange 2010:

left click - drag and drop from mailbox to public folder = move mail.
left click - drag and drop from public folder to mailbox = copy mail.
left click drag and drop from PF to PF = copy mail.

Exchange 2013:

left click - drag and drop from mailbox to public folder = move mail.
left click - drag and drop from public folder to mailbox = move mail.
left click drag and drop from PF to PF = move mail.

Does anyone know of a way to change behavior on drag and drop back to copy as the default?

Thanks