Right-Clicking Chat Field & Spell Checking Not Working

K-BASH 

You might be being forced to update to the latest Public preview by a Teams Update Policy set up by an admin! This may be why you do not see the preview options in teams

when you re-install.. if its force it will basically update as soon as you restart it so it may "seem" like you downgraded but it actually upgraded between tests, double check your version again!

We have our "Teams Update Policy"  set to "Users can opt in" hence why I have the option to "check" or "Uncheck" the option. this can be set to be forced by an admin so worth checking!

To check this you will need a Office 365 Teams or office 365 Global Admin account
Login to the http://You%20might be being forced to update to the latest Public preview by a Teams Update Policy set up by an admin! We have ours set to "Users can opt in" hence why i have the option to "check" or "Uncheck" the option. To check this you will need a Office 365 Teams or global Admin and Go to Teams -> Teams Update Policy

select the policy that applies to you and your users 

And ensure the "Show teams preview features"  are not set to either "On for users in Current Channel (Preview)" or "On for everyone"

Best practice would be to have global policy set to "off" and then have separate policy for thoes to "opt in" or if you have a small group of user that absolutely need a preview feature create a separate "On" policy to target just that group.

ps I'm not a Microsoft representative I'm just another admin!