Gelee and jelly are easily confused words.
The spell-check application of most word processing software programs would not catch a slip-up of these two words. Spell-check is looking for words that aren’t in its dictionary, and words that resemble words in its dictionary but are possibly spelled wrong. Spell-check isn’t perfect. It doesn’t know and can’t guess what word you wanted or what word you meant, it can only judge the words on the page. If you used words that are all spelled correctly, it gives you a pass anyway.
Autocorrect suggests words that start with the same letters. It suggests what word you may want to save time, but quite often, its suggestions couldn’t be more off base and produces humorous results.
Gelee is a noun. It is a suspension substance used for medical or moisturization purposes.
Jelly is a noun. It is a suspension made from fruit pectin that is used for sandwiches and cookies.
The following story uses both words correctly:
After a long day of administering medical tests and applying gelee to plastic sleeves and equipment, Gelasio sat down to his favorite lunch: fritos with a peanut butter and jelly sandwich.