The main known limitation with structure101 for Ada is that nesting below the subprogram-level is not supported. Nested subprograms will simply not be shown in the model. Packages that are nested within a subprogram will appear in the model at the root level (i.e. outside the subprogram). A sub-unit (separate) of a package within a subprogram scope will have a "has stub" relationship on the parent subprogram. Other similar effects may be noticed.