Currently, TitledAttachmentFileWidget use ProjectAssetsQuery to retrieve the "dmn" files.
Implicitly, this means that if (for whatever reason) dmn editor is disabled, the dmn file are not retrieved. Wording differently, this creates an implicit dependency between scenariosimulation and dmn editor.
Fix it so that TitledAttachmentFileWidget could find dmn files regardless of dmn editor.
Look at left dock that shows all the files of the project.