The print button in the toolbar plainly utilizes the print functionality of the browser, therefore, it cannot be extended.
As for DIV mode, it is expected the whole page to be printed, as there is no iframe to which the print method to be called.
Using the iframe mode, printing should be working, also, toggle full screen. Testing with this online demo--http://demos.telerik.com/aspnet-ajax/editor/examples/overview/defaultcs.aspx
--I am unable to reproduce the issue.
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