Can I use "use cases" / exentded "use cases" with direct associations ? The system does not offer the solid line shape, only dotted lines.
The dotted line is the standard for connections in UML 2.5. ( specification: http://www.omg.org/spec/UML/2.5/PDF/ Page 687 : UML shapes and edges).
Direct associations only work between Actor and "use case" / extended "use case".