I’m a big fan of keyboard shortcuts. So I was really disappointed when they did not work in Eclipse when I switched to Xfce from Gnome.
My first idea wast to review the Eclipse shortcuts, but they were correctly set. I then looked at Xfce keyboard shortcuts (Settings Manager->Keyboard->Application Shortcuts) and only a few were listed there, none that conflicted with the Eclipse default shortcuts. A quick Google search did not point me to anything concrete, until I saw this Peter Butkovic post in Dzone.
It turns out you have to edit the ~/.config/xfce4/xfconf/xfce-perchannel-xml/xfce4-keyboard-shortcuts.xml file! The before mentioned post is extensive and covers every modification you have to do, but to make things easier, I made the edited file available (please backup yours first) here.