For simplicity in our examples, we have encouraged you to create system diagrams by pre-selecting applications in Application Designer. You can also create brand-new system diagrams from scratch that you populate from the System View without using Application Designer at all.
As you experiment with System Designer, you may at some point encounter the problem of an application being shown with a dashed red outline on a system diagram, which indicates that the definition of the application (required by the system) is missing. The most likely causes for you to check are as follows:
The application has been removed from the application diagram.
The project for the application is unloaded or not part of the solution.
The application definition on the application diagram was renamed while the system diagram was closed; thus, the two diagrams could not be synchronized. All you have to do is locate or rename the missing application or system, and the references will resolve correctly. Renaming an application or system that is referenced in a system while that system diagram is open is fine, as it will rename the reference.