Cursor Snapmode Problem

Hi,

I made a simple WaveformGraph and set cursor SnapMode as ToPlot.

My problem is the graph plot cursor along mouse y position (not x position).

For example, at following capture image, I placed mouse near (200,11) position, but snapped cursor placed near (40, 11), which I expect cursor to snapped near (200, 9).

How can I make cursor snapped along mouse x position ?

Regards,

Stellar