When I open Apple Preview to view a document and I want to drag/drop from my Desktop to a Spaces window, it will not let me. I've been dealing with this issue since upgrading to El Capitan, and I was wondering if there was anything on my end that I can do from a Settings standpoint to fix the issue. I have since upgrade to MacOS Sierra today and the problem persists. Please advise.
Before

After

MacBook Air (13-inch Mid 2013), iOS 10