GCodeGraphics corrupts display sometimes

I've been working on my customized QtVcp GUI and I've been having issues with the preview causing display corruption.  It doesn't always happen, nor have I found a consistent way to make it happen.  Usually it's fine until I load a file for preview, and then go to the tab in my GUI which has the GCodeGraphics widget in it.  Then it draws these huge black triangles over the top of the entire GUI.  Minimizing/maximizing doesn't help, nor does moving around the view inside the widget.

I am doing my development inside of a VirtualBox virtual machine using the standard LinuxCNC Bookworm ISO image.  It could very well be an artifact of the virtual graphics driver, but I have tried a number of different settings and made sure my guest tools are up-to-date with no change.  I haven't yet tested this GUI on my real hardware yet.  I've never seen stock Axis do this from years of past testing.

 
 

I have never used Virtualbox with qtvcp so have no experience.
I have not seen that specific problem on any of my systems either.
I would try a native system any see the difference.
Sorry i can't help further.

No worries, I figured I'd ask in case it was something someone else has seen. I was doing some integration testing on the physical machine yesterday and it was behaving fine, so maybe it is just a Virtualbox problem.

Unfortunately today I saw the exact same display corruption on my real hardware.  No virtual machine to blame. Whatever is happening, it's definitely part of the QtVcp screen.  If you pop up a dialog for example, it will tint the black parts of the triangles.

Now to figure out a path to debugging this...