When opening a Prefab Stage for a given Prefab, the stage can be opened either in isolation or in context.
It's only possible to open in context if the stage is opened via a Prefab instance of the Prefab Asset.
InIsolation | Editing in isolation means that you can edit a Prefab Asset on its own in Prefab Mode. |
InContext | Editing in context means that you can edit a Prefab Asset in Prefab Mode and still retain the context of the Prefab instance you opened through. |