xfce4 custom keys presets inside terminal

1) Run xfce4-appearance-settings, go to Settings and activate Enable
editable accelerators
2) In XFCE Terminal with the mouse select the in Help the Contents that
also says F1 at the end
3) To delete the option, press ‘Delete’ or ‘Backspace’. Backspace edits
the F1 to Backspace, so it re-assigns another key.
If you want e.g. F3 as the ‘Help’ button (like old times) you press F3