How to completely reinstall Wolfram Workbench on linux

I've messed up my Ubuntu install, I've changed some pathnames I shouldn't have (don't know which ones exactly though), and after that Wolfram Workbench was not launching anymore. I uninstalled it by erasing the folder /usr/local/Wolfram and the workspace, then reinstalled it at the same place.

Workbench is now launching but the editor is still messed up, as you can see in this screenshot, this is all I get and I can't interact with:

When I launch Wolfram Workbench via command-line, I get the messages:

(Wolfram Workbench:5188): LIBDBUSMENU-GTK-CRITICAL **: watch_submenu: assertion GTK_IS_MENU_SHELL(menu)' failed