LayersPanel

Fifteen switches for what the sky map draws, grouped into objects, figures and the observer's own frame of reference. Composes <ToolPanel> and <Toggle>.

It carries no geometry and no idea of open: on the map it lives in the left tool column and InstrumentBar decides when it is on screen. The four atmosphere switches that used to sit at the bottom of this list are in SkyConditions, beside the Bortle slider they argue with.