Bug 124430 [Smoke][Regression][RCP]Library explorer keep gray even you add library file in Preferences.
Description: Library explorer keep gray even you add library file in Preferences. Steps to reproduce: 1. New several library files and add them through Window-->Preferences menu. 2. New a report and open Library Explorer view. Expected result: Library files display inside it. Actual result: It is gray with nothing inside. I cannot find add button in Library Explorer to add a library file,either.
UI/org.eclipse.birt.report.designer.ui.lib.explorer/src/org/eclipse/birt/report/designer/ui/lib/explorer/LibraryExplorerView.java
* the ID
	 */
	public static final String ID = "org.eclipse.birt.report.designer.ui.lib.explorer.view"; 
	private String defaultText = Messages.getString( "LibraryExplorerView.defaultText.notAvailable" ); 
	private Map pageMap = new HashMap( );
	/**
	 * default constructor
	 */
	public LibraryExplorerView( )
	{
		super( );
	}
	/**
	 * Creates and returns the default page for this view.
	 * 
	 * @param book
	 *            the pagebook control
	 * @return the default page
	 */
	protected IPage createDefaultPage( PageBook book )
	{
		MessagePage page = new MessagePage( );
		initPage( page );
		page.createControl( book );
		page.setMessage( defaultText );
		return page;
	}
	/**
	 * Creates a new page in the pagebook for a particular part. This page will
	 * be made visible whenever the part is active, and will be destroyed with a