Show the "Maximum Draw Type" for empties and cameras in case they work

as duplicators.

This property was always hidden in the UI for empties and cameras. It
doesn't make sense for the objects themselves (they are wires-only), but
also gets inherited by duplis. Now show it greyed out if not used, but
make it available for duplicators.

release/scripts/startup/bl_ui/properties_object.py

@@ -206,6 +206,7 @@ class OBJECT_PT_display(ObjectButtonsPanel, Panel):
         obj = context.object
         obj_type = obj.type
         is_geometry = (obj_type in {'MESH', 'CURVE', 'SURFACE', 'META', 'FONT'})
+        is_wire = (obj_type in {'CAMERA', 'EMPTY'})
         is_empty_image = (obj_type == 'EMPTY' and obj.empty_draw_type == 'IMAGE')
         is_dupli = (obj.dupli_type != 'NONE')
 
@@ -237,9 +238,13 @@ class OBJECT_PT_display(ObjectButtonsPanel, Panel):
         split = layout.split()
 
         col = split.column()
-        if obj_type not in {'CAMERA', 'EMPTY'}:
+        if is_wire:
+            # wire objects only use the max. draw type for duplis
+            col.active = is_dupli
+            col.label(text="Maximum Dupli Draw Type:")
+        else:
             col.label(text="Maximum Draw Type:")
-            col.prop(obj, "draw_type", text="")
+        col.prop(obj, "draw_type", text="")
 
         col = split.column()
         if is_geometry or is_empty_image: