Fill Color Disappears in Parallel Projection Top View

In a 2D floorplan, I filled the walls with black. In top view, the color completely disappears and when I orbit around, the surface gets all shimmery, switching between white and black. This has never happened before and I don’t know how to fix it. Please help!

It looks like you have two faces occupying the same space… the shimmering you are seeing is called Z-fighting and it happens when the two surfaces battle to see who gets drawn to the screen first. Best to erase or hide one of the surfaces.

So easy! Thank you so much.