Some objects (tables, procedures, functions) are missing when trying to generate ddl. (4226346)

Some objects (tables, procedures, functions etc) are missing when trying to generate ddl. Go to Model | Generate DDL Script. All objects are listed checked in the "Select List" and in the "What to Generate" tabs. And both "Child and Parent Tables are Generated" option is selected. But then the ddl is generated, not all objects are included in the script.

A model consists of 19 objects only has a script for 13 objects. Why are 6 objects not included?