From the described behavior, seems like there is something specific in the content of the documents that RadPdfViewer cannot read. This could be related to an issue or a missing feature in the control and not likely to the orientation of the document. However, we will need to test the documents in order to say what exactly the reason behind the experienced issue is.
RadPdfViewer comes with a RadToolBar in its UI. You can find more information on how to add the toolbar and wire it with the commands of the viewer in the Getting Started
Hope this is helpful.
Telerik by Progress
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