Use Subscript in legend of bar chart

I currently use a barchart element, which works great, however I am trying to adjust the text in my legend by writing R_{PD} (the PD should be in the subscript of the R, however I have not found a way of doing it. I tried using the HTML < sub> tag, however that does not work either. I would appreciate the help, thank you

Hi @gabel160,

This isn't supported at the moment.

Thank you for your fast help