Hi @datanixon -
Currently this is not possible but it’s a great feature request.
Here is a workaround to get a reference line on the x-axis, it’s rough, but could work depending on your use case.
Step 1 - Create an event dataset with your event dates and descriptions. You will also need start and stop events that match the date range in your visual.
Step 2 - Create a free-form bar chart visual using the event dataset, remove all border/line elements removed. Check the “show date gaps” under X-axis
Step 3 - Line up your start and end lines with your main data visual.
Step 4 - Set the colors of the bar chart lines. I’ve set the start/end to white to “hide them”
Result:
