The following occurs on Sheet1 only of a specific workbook.

Any word, correctly spelled or misspelled produces this from the Spell checker on the Review tab of the ribbon.

I get the Spelling: English (U.S.) dialog box as expected.
Regarddless of the word I have selected to spell check, the "Not in Dictonary box" displays "Tx" (no quotes).
In the Suggestion: box it offers TX, Tax, Tux.

On other worksheets in the same workbook the spell checker works fine as well as a new workbook and any worksheet in it.

Any clues as to what is going on with this particular sheet?

Thanks.
Regards,
Howard

Any clues