Read Only Ranges are protecting parts of the document from editing. The Spell Checker should edit the word in order to correct the error in it, but the restrictions form the read only range does not allow it. Usually ranges of this type are typed before showing the document, so you can check their correctness either by yourself or using the DocumentSpellChecker class. The next snippet shows how to spellcheck the current selection and you can use it in code before inserting the read-only range.
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