@Override
	public void domainObjectChanged(DomainObjectChangedEvent ev) {
		for (int i = 0; i < ev.numRecords(); ++i) {
			DomainObjectChangeRecord doRecord = ev.getChangeRecord(i);

			EventType eventType = doRecord.getEventType();
			if (eventType == DomainObjectEvent.RESTORED) {
				domainObjectRestored((Program) ev.getSource());
			}
			else if (eventType == ProgramEvent.FUNCTION_REMOVED) {
				ProgramChangeRecord rec = (ProgramChangeRecord) ev.getChangeRecord(i);
				Function function = (Function) rec.getObject();
				if (function != null) {
					removeFunction(function);
				}
			}
		}
	}
Overridden to listen for two event types:
<li>Object Restored: In the event of a redo/undo that affects a function
being shown in the comparison provider, this will allow tell the provider
to reload</li>
<li>Object Removed: If a function is deleted, this will tell the provider
to purge it from the view</li>
Ghidra/Features/CodeCompare/src/main/java/ghidra/features/codecompare/plugin/FunctionComparisonPlugin.java