void paintNavigation(Graphics g, int viewHeight, int width, AddressIndexMap addrMap) {
			for (MarkerSetImpl markers : markerSets) {
				if (markers.active) {
					markers.paintNavigation(g, viewHeight, width, addrMap);
				}
			}
		}
Use this close listener approach instead of plugin events, since we don't get a
ProgramClosedPluginEvent when a trace view is closed, but we can listen for its
domain object closing, which works for plain programs, too.
Ghidra/Features/Base/src/main/java/ghidra/app/plugin/core/marker/MarkerManager.java