Problem changing Break by dimension in Scatter Chart via Switchable Dimensions plugin

Hi all,

I've been able to switch dimensions for both category and break by panels in a bar chart using the official Switchable Dimensions plugin but need to do this for a scatter chart. I cannot get the break by panel to change. I can manipulate the others (x-axis, y-axis & point).

Does anyone else know where I'm going wrong?

Thanks, Andrew