Patterns are not being checked very well in the style editor. For example, a bass pattern (X 8 4) causes everything to freeze (The 8 is the problem.) Partly this is due to the old method of error checking being removed in the process of refactoring. The error checking should be done in the pattern constructor or factory, not in the GUI. Of course the problem would be reported through the GUI. This should be combined with the normalization of pattern representations, as there are too many conversion currently (from String, to S expression, to pattern object, etc.).