I have a problem to show web addin button on a ribbon. My addin is shown only when I press "Apps" button.
However, it works for other add-ins.
I tried to compare manifests of my add-in and "Add-in Command Demo", but I couldn't find what causes "..Command Demo" to be shown and my not.
I've found the similar question (more or less) Outlook web addin in ribbon
However I think my case is different. There the addin "Script Lab" not shown, but in my case that addin is shown. And there is not clear answer.
Some time ago it worked as designed. But Microsoft made some changes and it stopped to work.
I am talking about New Outlook and OWA.
On old Outlook (2019) the button is shown on a ribbon as designed.