Dear GraniteStateColin,
Good day! Thank you for posting to Microsoft Community. We are happy to help you.
Based on your description, I understand that you have a concern with 'Can we highlight MS Teams "Tabs"?'.
After thorough research and consulting, it’s been concluded that there is no option of spellcheck correction through keyboard for outlook on the web; this is only available in office desktop programs, such as outlook, where you may go to "File" > "Options" > "Mail" and then "Spelling and AutoCorrect"; You can activate spell check in Outlook emails by ticking the "Check spelling as you type" box and the "Mark grammar errors as you type" settings in the Proofing editor. As a result, in web-based outlook, this may be depending on the browser used.
We apologize if we are not able to meet your requirements; however, thank you for bringing this to our attention, we will surely raise your concerns to our Product Team and hopefully this can be considered in the future updates.
In the meantime, you may also create an entry as a feature suggestion in the Feedback Portal at Outlook · Community (microsoft.com), Other users may vote it and make it more visible to the dedicated team so that it may be considered for future upgrades.
For other concerns, please do not hesitate to add you post in the Microsoft Community Team.
Thank you for your cooperation and understanding.
Sincerely,
De Paul | Microsoft Community Moderator