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
else if ( validateContainer )
		
		{
			if ( targetHandle.getContainer( ) == null )
			{
				return CONTAIN_NO;
			}
			if ( !targetHandle.getContainer( )
					.getDefn( )
					.getSlot( targetHandle.getContainerSlotHandle( )
							.getSlotID( ) )
					.isMultipleCardinality( ) )
			{
				
				return CONTAIN_NO;
			}
			if ( targetHandle.getClass( ).equals( childHandle.getClass( ) ) )
			{
				
				return CONTAIN_PARENT;
			}
			return targetHandle.getContainer( )
					.canContain( targetHandle.getContainerSlotHandle( )
							.getSlotID( ),
							childHandle ) ? CONTAIN_PARENT : CONTAIN_NO;
		}
		return CONTAIN_NO;