We use Drawboard PDF on a Surface Pro 4 in our production facility. Recently we have started seeing a transparent image of the most recently used Drawboard PDF document remaining on the display, even if Drawboard PDF is not running. Other programs can be opened and used but the Drawboard image makes it difficult to see the program screens.
Oddly, the image does not immediately go away when restarting the Surface. After restarting and signing-in, the middle of the Surface screen shows no sign of the image but closer to the edges of the Surface the image can still be seen. After a few minutes the image is completely gone.