When choosing “Find SID/STAR” and simBrief cannot find a SID or STAR that connects to the route, it shows a warning dialog and indirectly encourages the user to find another route which can connect to a procedure.
It makes sense most of the time, but some airports do not have SIDs, STARs or either, and in that case, showing a dialog with an option to “Find New Route” does not make nearly as much sense, and can theoretically do more harm than good (perhaps the current route is valid and/or the best for the airport pair).
Basically, I think it would make sense for simBrief to assume “Only Find SIDs” if the destination airport has no STAR procedures, and assume “Only Find STARs” when the departure airport has no SID procedures, without presenting the dialog or offering to find a new route.
Not sure what does or should happen when neither departure nor destination have procedures.
Regards,
Tim