Sometimes, when using the drag and drop method to move emails, I'll click and hold on an email, start dragging it, and as I move the mouse over another folder before I release the mouse button (i.e. drop), Outlook will automatically switch to that folder or cancel the drag and drop operation and move the email to that folder. Again, this happens before I release the mouse button. I've spent several hours trying to find solutions to this on the Internet, but so far I haven't even found any other complaints of this problem.
Please note, I've already ruled out the mouse as the issue. This only happens in Outlook 2013. If I revert to Outlook 2010, it works fine with the same mouse. I also experience the issue with other mice in Outlook 2013.
I've noticed that when this happens, if I continue to move the mouse around (before releasing the left mouse button), it's still in dragging mode, but won't let me drop anywhere, and the email has already been moved.