No category list displayed in contacts sidebar

I am using eM Client 7 and have successfully imported 180+ contacts names and email addresses from a .csv file.

I have also created about 20 new categories.

However, none of the categories are displayed in the contacts sidebar. Even when I add a new contact manually and select one of the pre-existing categories, there is nothing displayed.

At the moment, the only way to display groups is by custom search folders, which is not ideal.

Please see screenshot:

Thank you in advance.