Hi Longsan,
So I tried to reproduce the issue you were seeing and I believe I know what is going on. If you zoomin and the max and min of the axes are smaller than the cursor position, the cursor will no longer be in the viewing area of the graph. Therefore, you would want to reposition the cursor after you zoom in. For example, in Visual Basic you could use the command
CWGraph1.Cursors(1).XPosition to change the position. I thiss out and it seems to work correctly. Let me know if try this and you are still having trouble.
Thanks,
Caroline
National Intruments
Thanks,
Caroline Tipton
Data Management Product Manager
National Instruments