private BookmarkNavigator getBookmarkNavigator(BookmarkType type) {
		if (type == null) {
			return null;
		}
		String typeString = type.getTypeString();
		BookmarkNavigator nav = bookmarkNavigators.get(typeString);
		if (nav == null) {
			nav = new BookmarkNavigator(markerService, currentProgram.getBookmarkManager(), type);
			bookmarkNavigators.put(typeString, nav);
		}
		return nav;
	}
Get or create a bookmark navigator for the specified bookmark type

@param type the bookmark type
@return bookmark navigator
Ghidra/Features/Base/src/main/java/ghidra/app/plugin/core/bookmark/BookmarkPlugin.java