My understanding from the documentation is that the new add_hline() would create a line that spans the entire plot.
Yet, in my use case, when I added one to a plot that has a categorical x axis with 65000 values (numbered 0 to 65000), the line only spanned values 0 to 1 in the x axis.
I looked at the graph in chart_studio, and indeed, it is set to start=0, end=0, relative to: “X”…