Someone did it modifying the eh.class file and replacing it in the jar file.
Photo from the thread
I tried using this old method in the new way Minecraft sort the versions, but it did not worked, the version folder does not appear in the minecraft version selection menu,maybe the eh.class file changed with the years in how works.
If someone could help me with this.
minecraft is obfuscated a different way in every version, so the eh.class has a different name in 1.9. You can just make a resource pack that changes the textures to the dirt background (but it still will move). Using MCP, if you go to the drawPanorama function in GuiMainMenu (in net.minecraft.client.gui), and replace all instances of this.panoramatimer with a constant, then the background shouldn't change. The names of things here may be different because I am using 1.12.2.