Thank you for your reply,
I just tried this on 2 machines, the desktop on which I reported this first, and the MSI laptop. They both still have this problem with Lazarus 1.0.2. I uninstalled lazarus by purging with dpkg the fpc, fpc-src and lazarus packages, and removing the .lazarus directory under my home directory, and install the new DEB packages.
Everything looks fine, but as soon as I open the Lazreport designer, the gray panel reappears. I can place bands, texts and pictures, nothing appears in the designer, but when I do a preview they show up in the report. I also checked I can add pages, in various formats and orientations, they do not appear in the designer except for the tab, but they all show up in the preview, with correct size and orientation.