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 true;
		if ( getSlot( slotId ).getCount( ) > 0
				&& !slotDefn.isMultipleCardinality( ) )
			return false;
		return true;
	}
	/**
	 * Checks whether the element to insert can reside in the given module.
	 * 
	 * @param module
	 *            the root module of the element to add
	 * @param slotID
	 *            the slot ID to insert
	 * @param element
	 *            the element to insert
	 * @return false if the module is a library and the element to insert is a
	 *         template element or its content is a template element; or the
	 *         container is report design and slot is component slot and the
	 *         element to insert is a template element or its content is a
	 *         template element; otherwise true
	 */
	private boolean canContainTemplateElement( Module module, int slotID,
			DesignElement element )
	{
		
		
		IElementDefn defn = MetaDataDictionary.getInstance( ).getElement(
				ReportDesignConstants.TEMPLATE_ELEMENT );
		if ( element instanceof TemplateElement )
			return canContainTemplateElement( module, slotID, defn );