Hello, Fabrice,

Thank you for bringing this to our attention.

Currently, the possible solution that I can suggest is to detect when the viewer is resized and reload the problematic document. This approach seems to work on my end and the document is displayed properly. The following code snippet better illustrates the idea:

         this.radPdfViewer1.SizeChanged += RadPdfViewer1_SizeChanged;

        private void RadPdfViewer1_SizeChanged(object? sender, EventArgs e)
        {
            radPdfViewer1.FitFullPage = false;
            radPdfViewer1.UnloadDocument();
            radPdfViewer1.LoadDocument(DocumentName);
            radPdfViewer1.FitFullPage = true;
        }

Please give this approach a try and see how it works on your end.

Regards,
Dess | Tech Support Engineer, Principal
Progress Telerik