I just noticed that you have a trailing comma after true:
“openhab.useRestApi”: true,
I’m not sure if that is causing any problem, but just in case I would remove it.
Then I found the following comment after I couldn’t get it to work myself (I’m using the official Docker container as well):
So you first need to open an .items file or a .sitemap file then in the left vertical icon bar you should see a new icon appearing. This icon is the openHAB logo. Click on it and you should see your items and things.
(It’s very well possible that it worked all the time for me but that I just didn’t notice the openHAB icon in the left bar)