The only way I can get to categories is by using the Ribbon. I can't figure out how to display the category icon in Office Outlook 2013. Similar to the flag icon you could click on the category icon to set the Quick Click category, or right click on the icon to select other categories.
In previous versions of Outlook there were little icons next to the flag icon in the messages pane. It is present if you turn off the reading pane to drop to a one line view, but that is not practical. Like the removal of the Quick Click category field in the message list. Outlook 2013 introduced a number to changes to existing features we've all grown to love and most of the changes aren't really for the better.
