UI:

* Fix context.cloth, was not being set correct.
* Fix errors with context pinning, scripts should
  not assume context.object to be there.
* Always show preview even if e.g. the material is not
  set, to keep ID buttons from jumping while you're
  using them.

release/ui/buttons_data_camera.py

@@ -14,7 +14,7 @@ class DATA_PT_camera(DataButtonsPanel):
 	__label__ = "Lens"
 	
 	def poll(self, context):
-		return (context.object.type == 'CAMERA')
+		return (context.object and context.object.type == 'CAMERA')
 
 	def draw(self, context):
 		layout = self.layout
@@ -87,4 +87,4 @@ class DATA_PT_camera_display(DataButtonsPanel):
 		col.itemR(cam, "draw_size", text="Size")
 		
 bpy.types.register(DATA_PT_camera)
-bpy.types.register(DATA_PT_camera_display)
+bpy.types.register(DATA_PT_camera_display)