In Microsoft SQL Server 2016 Express Management Studio (July 2016) cannot design a new or existing table.
Image 1: click on the tables node. Where is the menu option to add a new table?
Image 2: Click on existing table. Where is the menu option to edit an existing table?
Version: SQL Server 2016 Management Studio (July 2016)
Thanks!
This has been reported as a bug:
Microsoft Connect
social.msdn
Microsoft released a hotfix for this issue already. You can download it here: https://msdn.microsoft.com/en-us/library/mt238290.aspx
If you uninstall the July edition and re-install the June edition, things will be back to "normal" for you. You do lose the Azure support, however.