I'm using a Microsoft Office keyboard, which has dedicated buttons for Cut, Copy & Paste. I was able to choose that model inside the keyboard settings GUI of Xfce, which creates matching XF86Cut, XF86Copy and XF86Paste event entries. Cut, Copy & Paste works flawlessly afterwards inside Firefox and LibreOffice, since they natively support the defined XF86xxx events.
However Xfce (or Gtk) doesn't take care of these events.
xdotool key ctrl+x shortcut entries for the corresponding buttons inside the Xfce keyboard settings GUI, but it seems xdotool always requires the respective window ID to be given, so this doesn't work.
Any other ideas on how dedicated cut, copy & paste keys could be made usable within Xfce?