Hello Ian and Emanuel,
Thank you both for writing.
What I believe is happening is that you are showing the print preview dialog not as a modal dialog. And by the time the print doc rerenders the grid after you change the margins the column visibility is set back to visible. I would kindly ask you to verify that the print preview dialog is shown as a modal dialog. If this is the case, I would ask of you to send em your project or an example where you can extract the printing logic so I can investigate the situation further.
If you will be sending a project you will have to open a new support ticket. If you do so please mention this forum thread so we can update the information here as well.
I am looking forward to your reply.