I had Visual Studio 2015 Community and installed Office Developer Tools for Visual Studio 2015.
I selected File -> New -> Project.
From the New Project dialog, I selected Templates -> Office/Sharepoint -> VSTO Add-ins -> Word 2010 Add-in because I have Microsoft Word 2010 installed on my laptop and I would like to create an add-in to target it.
Clicking the Ok button opened up ThisAddin.cs in the editor.
I could even bring Visual Studio to show me the ThisAddin.Designer.xml and ThisAddin.Designer.cs files.
However, I could not open the add-in in the designer mode. Not only was there no designer, there was no sight of the Designer menu item either in the View menu on the toolbar nor in the context-menu when I right-clicked ThisAddin.cs. Also, the Toolbox did not display any items for me to use.
The same thing happened after I installed Visual Studio 2017 Community and selected Office Tools to be installed during the installation process.
That makes me wonder if I am doing something wrong or if the Community editions do not support VSTO?