Hierarchy and WED

I just finished fixing some bugs in WED regarding the hierarchy view. (To get a sense of what a hierarchy view is like, try AC3D...)

In WED, the contents of your airport layout are viewed in a hierarchy view. This is where you reorder your runways and rename entities. You can also group entities (as many times as you want) to help organize your layouts. (The groups will not be visible in the final apt.dat.)

An airport is, in a way, sort of a super-group...it's a group of "stuff" (runways, taxiways, etc.) plus it has its own information.

But this leads to some tricky situations:

• You can't have an airport inside another airport.
• You can't have a runway outside an airport.

The result is that there are a number of grouping and drag & drop combinations in the hierarchy that are simply illegal. Cris and I debated this a bit and what we have now is: commands that would produce illegal results simply cannot be executed. (That is, the group command is grayed out if the new group would violate these rules, and the drag & drop won't show a legal drop if the new order would violate these rules.)

Once we get into beta we'll see how well this works. The alternatives include:

• Putting up a specific error message when an illegal configuration is made (annoying).
• Allowing illegal configurations and putting up an error message on export (by this time the whole file layout could be pretty badly messed up).
• Attempting to silently export the illegal configuration (unpredictable - there's really no good way to export an airport inside an airport).

Also, I am sure there are some illegal configurations I have missed...we'll have to catch those in beta too.