Trasnparent PNG on windows

Good morning (o;

Not sure if this is macOS only or not…but…

When I place a PNG image onto a main window which has transparency I can see in the background if it some rounded corners:

Changing the “Transparent” field has no effect…

Also visible in light mode:

Bildschirmfoto 2022-03-17 um 06.39.40

This is with 2021r3.1 on macOS 12.3…

thanks in advance

How do you place the png on the window? Do you use a backdrop in a canvas or the paint event of a canvas?

Hmm…I just dragged an ImageViewer onto the window and assigned it a PNG image…

Use a canvas with the paint event.

Yes, the ImageViewer has a border; it’s part of the control. The canvas is completely transparent (before you draw anything to it, I mean).