Bug 48364 PreferenceDialog can reopen empty
20031209 When you close the Preferences dialog with an entry other than the default selected you will get an empty entry in the dialog when you reopen STEPS 1) Open the preferences dialog 2) Select the Appearances page 3) Close the dialog 4) Reopen - Workbench will be selected and the contents will be empty
bundles/org.eclipse.jface/src/org/eclipse/jface/preference/PreferenceDialog.java
protected void handleSave() {
		Iterator nodes = preferenceManager.getElements(PreferenceManager.PRE_ORDER).iterator();
		while (nodes.hasNext()) {
			IPreferenceNode node = (IPreferenceNode) nodes.next();
			IPreferencePage page = node.getPage();
			if (page instanceof PreferencePage) {
				
				IPreferenceStore store = ((PreferencePage) page).getPreferenceStore();
				if (store != null
					&& store.needsSaving()
					&& store instanceof IPersistentPreferenceStore) {
					try {
						((IPersistentPreferenceStore) store).save();
					} catch (IOException e) {
						MessageDialog.openError(getShell(), JFaceResources.getString("PreferenceDialog.saveErrorTitle"), 
						JFaceResources.format("PreferenceDialog.saveErrorMessage", new Object[] { page.getTitle(), e.getMessage()})); 
					}
				}
			}
		}
	}
	/**
	 * Notifies that the window's close button was pressed, 
	 * the close menu was selected, or the ESCAPE key pressed.
	 * <p>
	 * The default implementation of this framework method
	 * sets the window's return code to <code>CANCEL</code>
	 * and closes the window using <code>close</code>.
	 * Subclasses may extend or reimplement.
	 * </p>