Forgets everything the registry learnt about the map an application tears down: the map, the
active basemap, the registered definitions, any activation still deferred on that map, and
the relief the terrain manager held on it.
Called when an application is unmounted (UIModule.destroy()). Without it the next map got
NO basemap: the active key survived, and setBaseLayer returns early on the key that is
already active — it was active on the map that went away. The definitions are registered again
by the next Baselayers.init.
Forgets everything the registry learnt about the map an application tears down: the map, the active basemap, the registered definitions, any activation still deferred on that map, and the relief the terrain manager held on it.
Called when an application is unmounted (
UIModule.destroy()). Without it the next map got NO basemap: the active key survived, and setBaseLayer returns early on the key that is already active — it was active on the map that went away. The definitions are registered again by the nextBaselayers.init.