When the screen is dark, the bezel is approximately 1/16" wide. However, there is a black strip around the entire perimeter of the screen which increase the actual by 5/16" for a total of 3/8".
The bezel size is not the entire story. The actual 23" screen size is nearly 1-1/4" smaller then the actual size. Measured diagonally, the picture on the screen measures 21".
When I installed the monitor, Windows loaded generic drivers that were at least 5 years old.
When I updated to the latest drivers from the LG website, the 1-/14" border remained in place.
The recommended screen size is 1920x1980. There is nothing larger available.
It may be that I am missing something in the set up but at this point I have no idea where to go from here to make the picture size fill the screen.