The WPF Report Is Messed Up or Different from Design-Time Preview
|Progress® Telerik® Reporting
|Q2 2012 and later
The report in the WPF ReportViewer is messed up or is different from the design-time preview.
The WPF ReportViewer displays the rendered report in XAML format, so external styles may affect the produced XAML that contains standard elements like Canvas, TextBlock, and more.
Try to exclude styles to check if they change the displayed content. Alternatively, try to export the report in a format like PDF.