background-color in preview (white) is misleading

[DaRolla]

I am used to PlantUML within IntelliJ (dark theme) and there the preview color is the same as in the text editor window (something near dark).

Since I am using this extension within VS Code (dark theme) the background-color within the preview is white.

But rendering the PNG the backgroud is transparent (which is correct), and the VS Code editor showing this PNG uses something that is wellknown by Photshop users: these dark blocks.