PropertyGrid BrowsableAttributes Bug?

Question

This seems like a bug:

the code below works fine:

this.propertyGrid1.SelectedObject = new Button();

the code below doesn't:

this.propertyGrid1.BrowsableAttributes = new AttributeCollection(
     new CategoryAttribute("Layout"));
this.propertyGrid1.SelectedObject = new Button();

Size, Location, ... Properties in PropertyGrid can't be expanded.