Bug 122289 [Smoke][Regression][SPM-Linux WS]Item can't be dropped to layout from library
Details: Item can't be dropped to layout from library Setp: 1.New a library and insert a label 2.New a report design and use library 3.Drop label from library explorer to layout Actual results: Nothing is dropped into layout. Not only use library in outline, but also in library explorer is no effect. But when I drop the label without use library, it will use library and label can drop in it.
UI/org.eclipse.birt.report.designer.ui/src/org/eclipse/birt/report/designer/internal/ui/util/UIUtil.java
* @param element
	 *            the element
	 * 
	 * @return true if the element is on the tree, or false else.
	 */
	public static boolean containElement( AbstractTreeViewer treeViewer,
			Object element )
	{
		ITreeContentProvider provider = (ITreeContentProvider) treeViewer.getContentProvider( );
		Object input = treeViewer.getInput( );
		if ( input instanceof Object[] )
		{
			Object[] inputs = (Object[]) input;
			for ( int i = 0; i < inputs.length; i++ )
			{
				if ( containElement( inputs[i], provider, element ) )
				{
					return true;
				}
			}
			return false;
		}
		return containElement( input, provider, element );
	}
	private static boolean containElement( Object parent,
			ITreeContentProvider provider, Object element )
	{
		if ( parent == null )
		{
			return false;