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
return ( (TableHandle) parent ).canPasteColumn( transferData,
					columnNumber,
					true );
		}
		else if ( parent instanceof GridHandle )
		{
			if ( isNew )
			{
				return ( (GridHandle) parent ).canInsertAndPasteColumn( transferData,
						columnNumber );
			}
			return ( (GridHandle) parent ).canPasteColumn( transferData,
					columnNumber,
					true );
		}
		return false;
	}
	protected static int handleValidateTargetCanContainByContainer(
			Object targetObj, DesignElementHandle childHandle,
			boolean validateContainer )
	{
		targetObj = unwrapToModel( targetObj );
		if ( targetObj instanceof DesignElementHandle )
		{
			return handleValidateTargetCanContainElementHandle( (DesignElementHandle) targetObj,
					childHandle,
					validateContainer );
		}
		if ( targetObj instanceof SlotHandle )
		{