Attempting email drag and drop in Thunderbird drags entire email window

I'm on a Mac running 10.12.4. Before the lastest Thunderbird update, I was able to drag and drop email attachments directly into a folder on my desktop. Now when I attempt this, the entire email window drags along with my mouse pointer making dropping impossible. I have to go back to Control-click or Save and navigate to the desired folder. This mostly happens with single attachments but not always. Multiple attachments work only if I don't click on the first attachments when attempting to drag but I have had instances where I couldn't drag at all. Something like this never happened before the last update.