The "Common_GridPagerText" property is read and applied currently in ViewMode="Grid" only:
<telerik:RadEditor id="RadEditor1" runat="server" Language="it-IT" >
<ImageManager ViewPaths="~/Images" UploadPaths="~/Images" ViewMode="Grid"
This is a feature that should be implemented for Thumbnails mode.
All the best,
the Telerik team
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