Bug 120218 Right click menu option to apply theme.
We should support the following right click menu. -- User right clicks int he report design layout area. -- The following menu items needs to be supported Theme --> Apply Theme -->Theme1 -->Theme2 ( similar to Apply style menu option )
UI/org.eclipse.birt.report.designer.core/src/org/eclipse/birt/report/designer/util/DEUtil.java
if ( element == null )
		{
			SlotHandle slotHandle = parent.getSlot( slotID );
			if ( slotHandle != null )
			{
				return slotHandle.getCount( );
			}
			return -1;
		}
		return DEUtil.findPos( parent, slotID, element );
	}
	/**
	 * Finds the position of the child element in the parent element with the
	 * given slotID
	 * 
	 * @param parent
	 *            the parent element
	 * @param slotID
	 *            the slotID
	 * @param child
	 *            the child element
	 * @return the position of the child element
	 */
	public static int findPos( DesignElementHandle parent, int slotID,
			DesignElementHandle child )
	{
		assert slotID >= 0;
		SlotHandle slotHandle = parent.getSlot( slotID );
		return slotHandle.findPosn( child );
	}