macman wrote:If I extract the component class and the JInternalFrame class and place them into a test case project, the problem disappear.
If you add back other classes, can you identify when the problem reappears?
macman wrote:It seems like Swing Designer try to parse/examine every class in the project/package when we click on the "design" tab of the main designer view.
No. Swing Designer only parses the class you are editing. Referenced classes are not parsed. Custom components are instantiated just like any other component (by calling their default constructors).
macman wrote:I've just sent you a project that reproduce the problem.
We tried your project on several different machines and several different versions of Eclipse and did not encounter any problems.
As an experiment, what happens if you create a new Eclipse install with only Swing Designer present and then load your project and test case?