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
* Part of: User-defined property system.
	 * 
	 * @param propName
	 *            The internal name of the user-defined property.
	 * @return The user-defined property definition, if any.
	 */
	public UserPropertyDefn getLocalUserPropertyDefn( String propName )
	{
		if ( userProperties == null )
			return null;
		return (UserPropertyDefn) userProperties.get( propName );
	}
	/**
	 * Gets the definition of a user-defined property defined in this element or
	 * somewhere up the inheritance chain.
	 * <p>
	 * Part of: User-defined property system.
	 * 
	 * @param propName
	 *            The internal name of the user-defined property.
	 * @return The property definition, if found, null otherwise.
	 */
	public UserPropertyDefn getUserPropertyDefn( String propName )
	{
		DesignElement e = this;
		while ( e != null )
		{
			UserPropertyDefn p = e.getLocalUserPropertyDefn( propName );
			if ( p != null )
				return p;