Spell Checker deletes the whole sentence?

Spell Checker deletes the whole sentence?

Hi, I recently signed up for your product.
    I encountered only one problem: the spell checker will underline the whole sentence when only one word is spelled wrong and thus, when I press on the correct option, it deletes the whole sentence rather than correcting the word.
For me, this is a big problem because I am a notoriously bad speller and rely on spell check. Unfortunately, if this continues, I will not be able to use this wonderful product.


Thank you for your time!