Walter -
Default should be ALL runways extended ONLY on destination airport with the option (by touching airport) to only extend one specified runway. The rationale is approaching airport one can see the geometry of airplane course to available runways...when you are assigned a runway by tower (or hear what the active is on radio) you can then extend only the runway you plan to land on.
All airports (destination or not) should have the option by touching, to turn on runway extensions for that airport...but the default should be to have them turned off.
In my humble opinion ;-)
Thanks for a GREAT product.
Steve