hi @bobi, the bug with the grid is related to using a transparent grid in your display mode. The default ghost mode should not have this bug
RH-77385 Drawgrid and DrawAxis options in Shade are not working when using a transparent grid
I couldn’t repeat the flickering materials issue you are seeing here. Is that still an issue?
As for FilletSrf, yes it looks the previews are doing something to the shading, I added:
RH-77386 FilletSrf and related commands preview shading issues