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
/**
	 * Returns the optional message id used to localize the display name. Note:
	 * set the display name id by calling the
	 * {@link #setProperty( String, Object )}method.
	 * <p>
	 * Part of: The name system.
	 * 
	 * @return Returns the displayNameID.
	 */
	public String getDisplayNameID( )
	{
		return (String) getLocalProperty( null, DISPLAY_NAME_ID_PROP );
	}
	/**
	 * Sets the unique ID for this element. The ID can be set only once, when
	 * the element is first added to the design.
	 * 
	 * @param newID
	 *            The id to set.
	 */
	public void setID( long newID )
	{
		id = newID;
	}
	/**
	 * Returns the unique element ID. The ID will be valid only if element IDs
	 * were enabled in the MetaDataDictionary.
	 * 
	 * @return The unique ID. Returns 0 if element IDs are not enabled.
	 */