I was wondering if it was possible to add a marker at a point, like :
    bottom: new Date(2012, 4, 10),
    left: 80
So I can add static values to the dynamic series...

My second question is : Is it possible to make the option "grid: true" only showing lines when there is a marker from a serie ? My Time Axis shows grid lines on each dates, but there is not data on each dates. I wanted to add lines on the dates where there is a data.

I tried to add a top Axis (Category) to make the grid lines only on the markers, but doing this just make the Time Axis not working fine.