drools-eclipse/org.guvnor.tools/src/org/guvnor/tools/views/RepositoryContentProvider.java
public Object getParent(Object child) {
        if (child instanceof TreeObject) {
            return ((TreeObject)child).getParent();
        }
        return null;
    }
public Object getParent(Object child) {
        if (child instanceof TreeObject) {
            return ((TreeObject)child).getParent();
        }
        return null;
    }
/*
(non-Javadoc)
@see org.eclipse.jface.viewers.ITreeContentProvider#getParent(java.lang.Object)