Editor Mode:
You are allowed to pick almost every object directly in the 3D viewer window except the Grass, the Sky, the Terrain and the Particle Emitter.
You may use the Transform Tools above the 3D viewer to Move/Rotate/Scale objects.
Director Mode:
You can only pick the Actors and the iProps.
The Transform Tools are disabled in this mode.
Editor Mode: Click the right mouse button on the objects to pop up the Right-click Menu in which various operation functions relevant to the object can be found.
Director Mode: Click the right mouse button on the Actor or iProp to pop open the Right-click Menu in which only the Move, Perform, Operate and their sub entries exist.