Issue with background when display window is very wide

[zaddi]

When the main window is maximized an a 4k display (or made wider than about 3126 pixels) there is a vertical band on the left side of the display where the background is not drawn correctly.  It shows a dark/black background instead of light grey in the title bar, behind the main display tabs and also in the status bar.

[zaddi]

Screenshots of the top left corner at two different window widths showing different amounts of the bad background.