Bug 151959 inappropriate screen operation
steps to reproduce: - create a report - add a grid item (3x3) - switch to Outline view - expand the grid item to see its rows and cells - select the grid item, and drag it into any of its own cell expected behavior: - is it an invalid screen operation? if it is, it should be banned actual behavior: - the grid item was disappeared surprisingly
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/core/DesignElement.java
return "report"; 
		else if ( this instanceof Library )
			return "library"; 
		if ( getContainer( ) == null )
			return getDefn( ).getName( );
		ContainerSlot slot = getContainer( ).getSlot( getContainerSlot( ) );
		ISlotDefn slotDefn = getContainer( ).getDefn( ).getSlot(
				getContainerSlot( ) );
		StringBuffer sb = new StringBuffer( );
		sb.append( getContainer( ).getIdentifier( ) );
		sb.append( "." ); 
		sb.append( slotDefn.getDisplayName( ) );
		sb.append( "[" ); 
		sb.append( slot.findPosn( this ) );
		sb.append( "]" ); 
		return sb.toString( );
	}
	/**
	 * Sets the element with the id reference.
	 * <p>
	 * Part of: Inheritance system.
	 * 
	 * @param baseId
	 *            The id reference element.
	 */
	public void setBaseId( long baseId )
	{
		this.baseId = baseId;
	}
	/**