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
*/
                        public void selectionChanged(SelectionChangedEvent event) {
                            IContentType contentType = (IContentType) ((IStructuredSelection) event
                                    .getSelection()).getFirstElement();
                            fileAssociationViewer.setInput(contentType);
                            if (contentType != null) {
                                String charset = contentType
                                        .getDefaultCharset();
                                if (charset == null)
                                    charset = ""; 
                                charsetField.setText(charset);
                            } else
                                charsetField.setText(""); 
                            charsetField.setEnabled(contentType != null);
                            addButton.setEnabled(contentType != null);
                            setButton.setEnabled(false);
                        }
                    });
        }
    }
    /*
     * (non-Javadoc)
     * 
     * @see org.eclipse.ui.IWorkbenchPreferencePage#init(org.eclipse.ui.IWorkbench)
     */
    public void init(IWorkbench workbench) {
        noDefaultAndApplyButton();
    }
}