I've lately seen a lot going on about the KDE Global Menu, so I gave it a shot. On Tumbleweed it's dead easy. This method also works around the width of f.e. LibreOffice menus.
- Right click on the existing panel, unlock the widgets
- Right click again ( on panel or desktop ), pick Add Panel > Empty panel
- Right click the newly created panel, pick Add Widgets > Global Menu ( double click it, or drag it to the newcly created panel
- Right click the newly created panel > Configure Panel > Screen Edge and drag the panel to the top of the screen.
- Next set the panel to auto hide.
- Logout, login and enjoy
FWIW, I already have the main panel on top, but a touch of the screen edge now shows the global menu. Only thing so far it doesn't work for is Firefox.