Bug 88878 [Preferences] File and Content Type pages should link to one another
There should be some mention of the relationship between content type and file association pages.
bundles/org.eclipse.ui.ide/src/org/eclipse/ui/internal/ide/dialogs/ContentTypesPreferencePage.java
IContentType[] contentTypes = manager.getAllContentTypes();
            for (int i = 0; i < contentTypes.length; i++) {
                IContentType type = contentTypes[i];
                if (type.getBaseType() == baseType)
                    elements.add(type);
            }
            return elements.toArray();
        }
        /*
         * (non-Javadoc)
         * 
         * @see org.eclipse.jface.viewers.ITreeContentProvider#getParent(java.lang.Object)
         */
        public Object getParent(Object element) {
            IContentType contentType = (IContentType) element;
            return contentType.getBaseType();
        }
        /*
         * (non-Javadoc)
         * 
         * @see org.eclipse.jface.viewers.ITreeContentProvider#hasChildren(java.lang.Object)
         */
        public boolean hasChildren(Object element) {
            return getChildren(element).length > 0;
        }
        /*
         * (non-Javadoc)
         * 
         * @see org.eclipse.jface.viewers.IStructuredContentProvider#getElements(java.lang.Object)
         */