From the information provided so far it is difficult to exactly define the reason for the described behavior.
Are there any RadEditor Context Menu configuration that would cancel the browser's context menu? Note that if there are, the configured context menus are mapped to DOM elements inside the content. Therefore, you could verify if right click to any element causes the same behavior.
As for the spelling, I am not sure what the exact issue is. The built-in spell checker, traverses all content and show all misspelled words, you cannot right click on a certain word and correct it. The only spell checker that can do that is the native browser's spell checker.
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