There have been some reports that specific versions of nVidia graphics drivers on Windows cause problems.
The symptoms are odd drawing problems, like multiple overlapping frames.
Try starting jOverseer without Direct3D usage for Java2D drawing.
Use the batchfile joverseer-no3D.bat:
update or install 1.16.19 or later. right mouse click on jOverseer shortcut on the desktop, select properties, change the Target to “C:\Program Files (x86)\JOverseer\joverseer-no3D.bat” press Apply and OK buttons. double clicking on the joverseer Icon will startup without the 3d options. references: https://www.nvidia.com/en-us/geforce/forums/game-ready-drivers/13/55070/19038-drivers-cause-distorted-video-in-java-apps/ https://docs.oracle.com/javase/7/docs/technotes/guides/2d/flags.html