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
SlotHandle targetHandle = (SlotHandle) targetObj;
			if ( targetHandle.getElementHandle( ) instanceof LibraryHandle
					&& childHandle instanceof ThemeHandle )
			{
				return CONTAIN_NO;
			}
			return targetHandle.getElementHandle( )
					.canContain( targetHandle.getSlotID( ), childHandle ) ? CONTAIN_THIS
					: CONTAIN_NO;
		}
		return CONTAIN_NO;
	}
	protected static int handleValidateTargetCanContainByContainer(
			Object targetObj, Object[] childHandles, boolean validateContainer )
	{
		if ( childHandles.length == 0 )
		{
			return CONTAIN_NO;
		}
		for ( int i = 0; i < childHandles.length; i++ )
		{
			if ( !( childHandles[i] instanceof DesignElementHandle )
					|| handleValidateTargetCanContainByContainer( targetObj,
							(DesignElementHandle) childHandles[i],
							validateContainer ) == CONTAIN_NO )
			{
				return CONTAIN_NO;
			}
		}
		return CONTAIN_THIS;