How to format xAxes tooltip on a perspective XYChart

Hi All,

I am trying to display historical data using a XYchart component in Perspective. I hope to use the xAxes tooltip to display time stamp, as below:
tooltips

Is there a way to format tooltip text independent of xAxes text? My axes are formatted as “M/d” because I don’t have enough space to put time there. But I do hope to show date and time on the tooltip. I am using the following string for tooltip format, but did not seem to change anything.
image

Can somebody point what I was missing? Thanks!