The styles of the web report viewer's toolbar are messed up

PROBLEM
The web report viewer's toolbar is messed up



SOLUTION
This usually indicates that the ReportViewer control has not been able to load its stylesheet due to one of the following things:

1. Missing preCondition attribute of the report viewer handler's registration in the <system.webServer>\<handlers> section, when the application is hosted on IIS7, i.e. the handler should look like this:
   

   <system.webServer>

   <handlers>

   <add name="Telerik.ReportViewer.axd_*" path="Telerik.ReportViewer.axd" verb="*" type="Telerik.ReportViewer.WebForms.HttpHandler, Telerik.ReportViewer.WebForms, Version=x.x.x.x, Culture=neutral, PublicKeyToken=a9d7983dfcc261be" preCondition="integratedMode"   />

   </handlers>

   <validation validateIntegratedModeConfiguration="false" />

   </system.webServer>

2. Check for runat="server" attribute in the web page's head tag - it is required.
3. Use a web debugging proxy (e.g. Fiddler tool) to see what is the response for the /ReportViewer.axd?name=Resources.ReportViewerInternal.css&version=x.x.x.x&optype=Resource request or any request of such kind.
4. If you have global styles or themes applied on the page - disable them temporary to verify if they are the culprit. If this proves to be the case, make sure that styles/themes do not affect html elements directly, but are applied through the CssClass property.

Note: Substitute Version=X.X.X.X with the exact assembly version you are using!