I use a program called Safehouse which creates an encrypted folder in which to store files. Since moving to DO 12 I can't drag from the encrypted folder into DO. I can drag into the encrypted folder. Windows explorer works OK.
Am I trying the correct thing?
On more investigation it is strange. If I run Safehouse Explorer from DO it works. If I create a link to Safehouse Explorer on the desktop and open that I can't drag and drop. I normally run it from a menu app which is like a shortcut. I can get it to work by running direct from Program Files in DO so it is not life threatening.
Have you launched the whole dopus.exe process elevated? If so, see here.
It was running as ADMINISTRATOR. Removing the setting has cured the problem.