To reproduce: - Add several paragraphs with SpacingAfter set to 0. - Export and then import using XAML format provider. - You will notice that the spacing is reset to the default value. Workaround: Paragraph para = new Paragraph(); para.SpacingAfter = 0.01f ; Resolution: This issue is addressed in the new version of the control - RadRichTextEditor. Please use the new control instead the RadRichTextBox.