Are user-drawn shapes always plotted against the x1, y1 axes?

I have a series of Plotly charts that plot multiple Y axes against a single X axis – imagine a timeseries plot where one trace represents voltage (against axis Y1) and another represents current (against axis Y2), so the order of magnitude of the Y-values is very different. I have added some of the built-in shape drawing features to the modebar to allow users to mark up the plot.

It appears to me that a user-drawn shape from the modebar is always drawn against the primary Y axis (voltage in this case), but I can’t find that in the documentation anywhere as a guarantee. I have 2 questions:

  1. Is it true that any user-drawn shape will be plotted against the Y1 axis?
  2. Is there any way to configure this, so that a user could draw one line against the “current” axis that would move as a user changes the scale of axis Y2? Right now on a multi-axis plot it appears that any drawn shape will move when the limits of the Y1 axis are changed, but stay still when the limits of the Y2 axis are changed.