Hi
I downloaded the newest demo to see if I could add a watermark to a document that is viewed in the Groupdocs.Viewer. 
I add the following (in red): 
    <%=  Viewer.ClientCode()
            .TargetElementSelector("#test2")
            .FilePath(“timesheet.xls”)
            .OpenThumbnails(false)
            .ZoomToFitHeight() 
            .Width(900)
            .Height(400)
            .Locale(“nb-NO”)
            .BackgroundColor("#777")
            .UseHtmlBasedEngine()
            .ShowThumbnails(false)
            .Watermark(“TEST WATERMARK”)
            %>
But no watermark appears. I see from other posts that there was a problem related to IE not showing it but I am using Google Chrome. I am of course using an unlicensed demo version. Is that maybe the problem?