Created attachment 811081 [details]
screenshots

Hello, mate-dock-panel does not work since Leap 15.0, but it's already the same
in mate 15.1

How to have the bug:
I have installed a fresh version of leap 15.1.
Choose mate desktop directly on the dvd installer.

Then i install the package mate-dock-applet from yast.

When i try to add it to a panel, it's added on the panel (picture1), if i click
somewhere on the panel i could have the "option" menu, but nothing works.
"settings" does nothing, no shortcut on the dock etc. 
(picture 2)

If i click on "about" it works (picture3).