private void updateMarkers(AddressSetView set) {
		if (markerService == null) {
			return;
		}

		if (markerSet == null) {
			// TODO: should we instead pick a reasonable color??
			Address minAddress = set.getMinAddress();
			Color color = service.getBackgroundColor(minAddress);
			if (color == null) {
				// not sure if this can happen
				color = MARKER_COLOR;
			}

			markerSet = markerService.createPointMarker(MARKER_NAME, MARKER_DESCRIPTION,
				currentProgram, PRIORITY, false, true, false, color, null);
		}
		else {
			markerSet.clearAll();
		}

		AddressRangeIterator iterator = set.getAddressRanges();
		while (iterator.hasNext()) {
			AddressRange range = iterator.next();
			markerSet.add(range);
		}
	}
A plugin to provider actions for manipulating the colors of the {@link CodeViewerService}.
Ghidra/Features/Base/src/main/java/ghidra/app/plugin/core/colorizer/ColorizingPlugin.java