Bug 156632 [Acceptance]Cannot paste theme when select Themes in Outline.
Description: Cannot paste theme when select Themes in Outline. Steps to reproduce: 1. New a library. 2. Select defaulttheme in outline and cut it 3. Select Themes and right click to paste the theme back. Expected result: Paste in context menu can be used. Actual result: Paste is gray
UI/org.eclipse.birt.report.designer.core/src/org/eclipse/birt/report/designer/util/DNDUtil.java
}
		if ( source instanceof StructureHandle )
		{
			return ( (StructureHandle) source ).getStructure( ).copy( );
		}
		return null;
	}
	/**
	 * Drops source data
	 * 
	 * @param source
	 *            source to drop
	 */
	public static void dropSource( Object source )
	{
		DeleteCommand command = new DeleteCommand( source );
		if ( command.canExecute( ) )
			command.execute( );
	}
	/**
	 * Gets handle of target
	 * 
	 * @param target
	 * @return handle of target
	 */
	public static DesignElementHandle getDesignElementHandle( Object target )
	{
		target = unwrapToModel( target );
		if ( target instanceof DesignElementHandle )
		{