Feature Request: Set background color without flood fill

[shannonturner]

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Right now maps have a transparent background which displays as white during editing.

You could flood fill to get a different color if you wanted, but being able to set a background color instead would make maps load a lot faster.

From Youtube:

Nice update! Can you make an option to change the background to any color? It would be more convenient than having to use the fill tool and select a color on the draw rail line thing.