Question: Safari download "icon" appears
When I download a file in Safari, a transparent gray-and-white "Safari" icon appears and remains on top of all other windows. It remains after I quit Safari, and only disappears after I reboot my Mac. This started happening in OS 10.12 and continues now that I have upgraded to 10.13.3. See screen shot. Thoughts?
iMac, OS X Yosemite (10.10)