Search for ExportToolTip by string in all themes' Telerik.ReportViewer.Silverlight.xaml files and change the bindings as follows:
Then double-check the keys entered in the resource files and make sure they corresponds to the following list: Silverlight ReportViewer TextResources
More details about the viewer's localization can be found in the Report Viewer Localization
The problem with the themes is logged into our system, and your Telerik points are updated to thank you for reporting it.
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