Roads Category and Spot Elevation

This is too weird not to write about it. I was asked to take a look at a file that would not let us apply a spot elevation. I did the usual things, check for the floor category visibility, no overrides to the linked floor(s), no filters, no underlay weirdness... no joy.

I compared it against a new view with no view template. The new view worked but the one with a view template assigned didn't. I tried turning back on all the model categories that were off in the view template. The Spot Elevation tool worked again. Hmmm...

I reset the View Template and then I turned back on each category that was off in the template, one at a time. When I turned on the Roads category the spot elevation started working again. WHAT??

That's more than a little bizarre since we've never been able to use the Roads category for anything. They don't even let us create an In-Place family using the Roads category. I imagine that it is something gone awry in this particular project file since this is the only one behaving this way but still...turning on the Roads category fixed it??