Million thanks for sharing this ..
I use dockbarx (in xfce) and as long as you can launch an app, you can just right click on the icon of the running app and pin it to the panel. Take a look at dockbarx ..
Dockbarx supports other window managers (like mate, gnome, etc) .. See also dockbarx on launchpad ..
Dockbarx has a nice GUI for customizing (unlike plank), and can group multiple windows from the same app.