Please test to display a Form with a single ReportViewer on it without using any other controls. For the purpose of the test download and test the latest available Telerik Reporting version Q3 2013.
If the issue still occurs, please elaborate on the scenario, the used controls and Telerik Reporting version, also attach a screenshot to illustrate the problem.
Feel free to open a support ticket and send us your details in it. We will update this thread for anyone concerned.
New HTML5/JS REPORT VIEWER with MOBILE AND TOUCH SUPPORT available in Telerik Reporting Q3 2013! Get the new Reporting version from your account or download a trial.