How to add row to grid using updateFromXML

I want to load a grid from XML, then add rows from a second XML. However, when I call updateFromXML, the rows from the first XML file are gone, and only the rows from the second XML are in my grid. I’m doing the following:

myGrid.loadXML(“myrows_part1.xml”);
myGrid.updateFromXML(“myrows_part2.xml”);

My part1 XML is of the form

<?xmlStr version="1.0" encoding="UTF-8"?> My row My row

My part2 XML’s id’s start where part1 leaves off:

<?xmlStr version="1.0" encoding="UTF-8"?> My row My row

After doing this, my grid only has rows 3 and 4. How can I see all four rows?

Thanks

Unfortunately the issue cannot be reproduced locally.
If it’s still occurs for you, pleas,e provide with a more detailed sample of your code or a complete demo/demo link, where the issue can be reconstructed.