@Nonnull
	public List<Problem> getProblems(@Nonnull Predicate<Problem> filter) {
		List<Problem> list = new ArrayList<>();
		synchronized (problems) {
			problems.values().stream()
					.flatMap(Collection::stream)
					.filter(filter)
					.forEach(list::add);
		}
		return list;
	}
@param filter
		Filter to pass problems through.

@return List of problems matching the filter.
recaf-ui/src/main/java/software/coley/recaf/ui/control/richtext/problem/ProblemTracking.java