private void removeOldTags() {
		Map<String, VTMatchTag> allTags = getAllTags();
		Iterator<VTMatchTag> iterator = excludedTags.values().iterator();
		for (; iterator.hasNext();) {
			VTMatchTag tag = iterator.next();
			if (!allTags.containsKey(tag.getName())) {
				// not in the new session
				excludedTags.remove(tag.getName());
			}
		}
	}
This differs from {@link #initializeTags()} in that this method will keep any excluded
tags when updating.
Ghidra/Features/VersionTracking/src/main/java/ghidra/feature/vt/gui/filters/TagFilter.java