OpenSUSE Leap 42.2. Application window disappear while dragging it to second display if default panel is placed vertically on primary display next to secondary display. Issue does not appear if panel is placed vertically on primary display on the opposite side of secondary display. Issue does not appear if window is moved by Alt+dragging. I can reproduce the issue with neon-useredition-20161114-0947 with Plasma 5.8.3.
*** This bug has been marked as a duplicate of bug 371199 ***