Air displays supress persistent effect

[ghost]

Go into the renderer options and enable element path persistence. Then enable any one of the three pressure/velocity displays.

Path persistence stays on but will immediately cease to render.

When going the other way (air then persistence), the air mode will be automatically disabled.

[jacob1]

Noticed this when looking into #579 last week. Decided not to fix that issue for now because I don't want to get into it at the moment, it's too complicated.

(probably won't fix this for a while either)

[ghost]

The way that persistence disables air (as in, the box becomes unchecked) implies an easy fix would be to make air disable persistence in the same fashion, surely?

Then it can all render properly while all the other persistence problems are ironed out.

[jacob1]

I don't know if that's intentional that air gets disabled. Renderer::AddDisplayMode removes all air display modes when adding a new one. So perhaps it is intentional, but it's done in a really obviously wrong way.