Table Builder is installed here at meta.discourse.org as well as on try.discourse.org, right?
I tried it on both. I can see the “Insert Table” option and the Table Builder opens, but when the table is done, I see it unformatted without any edit button.
I tried it on Firefox desktop, Firefox mobile and Chrome mobile.
What am I missing?
Edit: I installed it in a self hosted Discourse instance (3.0.2) and I have the same issue there.
I tested it on Linux/Firefox, Windows 10/Firefox, and Windows 10/Edge.