Hi Katerina, I’ve now checked this out, and reported a bug. Any material with a stroke component will preview just the stroke – no fill. I’ve tried this is all viewport shading modes. Same issue. Strangely enough – if you first draw an open shape with the pencil tool, then any shape will preview correctly! So it’s definitely a bug. I’ve sent a report, and I hope we get a fix soon. Thanks for mentioning this! 