private void updateListener(Program newProgram) {
		if (newProgram == program) {
			return;
		}
		if (program != null) {
			program.removeListener(this);
		}
		if (newProgram != null) {
			newProgram.addListener(this);
		}

	}
Default {@link BackgroundColorModel} for the ListingPanel where the color returned
for an index is based on that corresponding address having a color set in the
program's database. (You can "paint" colors over address ranges).
Ghidra/Features/Base/src/main/java/ghidra/app/util/viewer/listingpanel/PropertyBasedBackgroundColorModel.java