Creating Java UML Automatically in NetBeans 6.7

I have three packages in NetBeans 开发者_运维知识库6.7 that i want to generate a UML Class diagram automatically for. I have created the new Model by reverse engineering my project, but when i highlight all three packages under the 'Model' heading and select 'Create diagram from selected elements' i just end up with 3 green boxes. I can create separate diagrams by choosing the individual packages, but would ideally like a diagram that merged all three together. Is this even possible?

Thanks

Rather than just selecting the top level packages and hitting 'Create diagram from selected elements', expand the packages in the tree view and select the classes as well then hit 'Create diagram from selected elements'. That should show you the classes in the packages as well.