Configuring preferences and options in Outlook.com
You can 'vote' to have the icons put back -
https://feedbackportal.microsoft.com/feedback/idea/ef8342e1-3cd5-ec11-a81b-000d3a03dba2
It seems to happen from time to time... a big software company breaks the UX and then the users
have to vote to unbreak the thing they never voted to break in the first place.