Export PNG with transparent background
 

Is it possible to export a plot to .png while keeping the background transparent? I tried setting the property "ISTRANSPARENT" for both frame and page to "yes", but still I get a dark gray background in the exported image.

This is the version I'm using:
Tecplot 360 EX 2018 R2, Version 2018.2.0.92317 (Oct 16 2018)