No prob (almost) when viewing on Safari (macOS).
Parameter is slightly off (up one px) and almost the same size.
So the problem may be device-specific.
Or even Tableau Desktop Win-specific :-)
BTW, have you disabled Accelerated Graphics?
This would help with the 'black' Parameter selection, imho.
Chrome does bring it closer to the same size. My pictures are from Firefox.
They are still different though...seems like it's on my windows desktop version, on Tableau Public, and Firefox-a Tableau issue, not a user issue?
Firefox 58.0.2 on macOS --
exactly the same as Safari.
No need to post screenshots.
Imho, the problem would be localised
to your specific environment (rather win then ff).
Besides, what about turning OFF the Graphics Acceleration in TD?