Bug 56637 [Preferences] DialogMessageArea image is too large
Is the background color of the error shown by DialogMessageArea to be changed? Or do you intend to leave it as it is right now? The error message looks a little out of place in the current implementation (being surrounded by white space).
bundles/org.eclipse.jface/src/org/eclipse/jface/preference/PreferenceDialog.java
});
		((Tree) viewer.getControl()).addSelectionListener(new SelectionAdapter() {
			public void widgetDefaultSelected(final SelectionEvent event) {
				ISelection selection = viewer.getSelection();
				if (selection.isEmpty())
					return;
				IPreferenceNode singleSelection = getSingleSelection(selection);
				boolean expanded = viewer.getExpandedState(singleSelection);
				viewer.setExpandedState(singleSelection, !expanded);
			}
		});
		
		viewer.getControl().addHelpListener(new HelpListener() {
			public void helpRequested(HelpEvent event) {
				
				if (currentPage != null) {
					currentPage.performHelp();
				}
			}
		});
		viewer.setLabelProvider(new PreferenceLabelProvider());
		viewer.setContentProvider(new PreferenceContentProvider());
		return viewer;
	}
	/**
	 * Find the <code>IPreferenceNode</code> that has data the same id as the 
	 * supplied value.
	 * @param nodeId the id to search for.
	 * @return <code>IPreferenceNode</code> or <code>null</code> if not found.
	 */