Issue: When attempting to open an image for editing on an external monitor, the Photoshop window starts "ghosting" - making multiple copies of tool pallettes across the display. The image to be edited may not appear in the main editing window, instead showing a image of the previous Photoshop screen. If Photoshop is opened on the main laptop display, the image appears as expected.
Environment: Adobe Photoshop 2019, Dell DisplayLink Docking Stations (D3100, D6000), external monitors.
Resolution: Disable graphics acceleration in Photoshop by unchecking the "Use Graphics Acceleration" box at the following location: Edit > Preferences > Performance. This issue is caused by Photoshop expecting graphics acceleration which the Dell DisplayLink docking stations do not support.