Hi Aleks!
You can use the property nodes associated with graphs and charts to programmatically modify the cursors defined for the graph, and add them at run-time. One of the easier ways to do this is by modifying the Cursor List property of the graph. This property contains an array of clusters, with each cluster containing all of the information about a particular cursor. To add a new cursor to the graph, all you would need to do is add another element to this array of clusters and set the parameters appropriately. When you write to this property, it will update the graph on your front panel. You'll probably want to only show the user a few parameters and build the cluster yourself on the block diagram to make your program a little more user-friendly. Let me know if I can provide more information!
Cheers,
Matt Pollock
National Instruments