Thank you for writing.
In our online documentation, we have a list with the unsupported by the pdf engine features: http://www.telerik.com/help/winforms/pdfviewer-unsupported-features.html
. The described scenario could work in case you are familiar with the type of the document you are about to open, however, there is no such property.
We are going to need the problematic pdf files in order to perform further investigation. Please note that attachments are not allowed in forum posts, so you have two options either opening a support ticket or uploading them some cloud storage and sending me the link.
I hope this helps. Should you have further questions please do not hesitate to write back.
Do you want to have your say when we set our development plans? Do you want to know when a feature you care about is added or when a bug fixed? Explore the Telerik Feedback Portal
and vote to affect the priority of the items