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
{
				props.addAll( prop );
			}
			e = e.getExtendsElement( );
		}
		return props;
	}
	/**
	 * Returns a list of user properties that are defined only on this element.
	 * 
	 * @return The list of user properties.
	 */
	public List getLocalUserProperties( )
	{
		if ( userProperties == null )
			return Collections.EMPTY_LIST;
		return new ArrayList( userProperties.values( ) );
	}
	/**
	 * Checks if this element derives from the given element. The check is true
	 * if this element derives from the target, or if the target is an ancestor
	 * of this element.
	 * 
	 * @param element
	 *            The potential ancestor.
	 * @return True if the given element is an ancestor of this element, false
	 *         otherwise.
	 */
	public boolean isKindOf( DesignElement element )
	{