Running apps added to panel

I just upgraded from FC39 to FC40 via a spin. Last week when I opened an app (ie thunderbird) it showed up on the panel (which I autohide). Then I can minimize and later mouseover the panel and click on the icon to re-raise. How do I get the icon to show up in the panel when I run a program?

Thanks

This will happen automatically if you have a Task Manager or Icons-Only Task manager widget in your panel (the latter one is there by default). Maybe it got deleted somehow?

Found I needed to add the widget Task Manager to the panel