In a Map window, when you add a board to “Map boards” and you don’t select an image, you get to choose the background colour of the map window.
However, when you choose an image, the option to select a background colour disappears. This is a concern when you use horizontal and vertical padding to move the image away from the top left hand corner. The background colour of the map window will now be visible and it is white.
It would be a benefit to be able to change this colour as I would like to change the background colour to match the border of the image I select. This would avoid having a black bordered image having a glaring white background colour surrounding it.