Bug 228760 [Markers] Column orientation not stored when markers views are closed
If we re-order view columns by drag and drop or add/remove them using the preferences the values we ended up with are not restored on restart.
bundles/org.eclipse.ui.ide/src/org/eclipse/ui/internal/views/markers/ExtendedMarkersView.java
return categoriesToExpand;
	}
	/**
	 * Return the group used for categorisation.
	 * 
	 * @return MarkerGroup
	 */
	MarkerGroup getCategoryGroup() {
		return builder.getCategoryGroup();
	}
	/**
	 * Return the clipboard for the receiver.
	 * 
	 * @return Clipboard
	 */
	Clipboard getClipboard() {
		if (clipboard == null)
			clipboard = new Clipboard(viewer.getControl().getDisplay());
		return clipboard;
	}
	/**
	 * Return the content provider for the receiver.
	 * 
	 * @return ITreeContentProvider
	 * 
	 */
	private ITreeContentProvider getContentProvider() {
		return new ITreeContentProvider() {
			/*
			 * (non-Javadoc)