Strange behavior with Class embedded in Use Case

[chintsys]

I have a few levels of nested Use Cases in a EA9.0.907 model and a Class defined within one of the levels.  When I try to Associate the Class with the Use Case that contains it on a Use Case diagram, the Class embeds itself into the parent Use Case shape (i.e. one level up from the Use Case that contains this Class) and won't allow itself to be moved elsewhere on the diagram.  Is this behavior normal?