The default English dictionary we provide with the control contains only lower case words, as do most of the dictionaries that have been provided by clients
over the years. That said, RadSpellChecker actually transforms the words that are being checked ToLower() and searches in the dictionary with that result.
As to the SpellCheckUppercaseWords feature, this option allows to spellcheck languages that do not have a concept of distinct upper and lower case letters like Arabic, as well as all upper-case words, but you are right that it is pretty different than what you are looking for.
We actually haven't received similar requests until now, so could you please provide more details on your scenario? For example, what is the culture you are spellchecking in and are you creating your own dictionary?
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