Is there a shortcut (missing?) to move tab in xfce4 terminal app?

Plain CtrlPgUp and CtrlPgDn should work to cycle tabs. There's a option in the "Tabs" menu which shows the shortcuts.

If you don't see the menu bar, right click inside the terminal window and pick "Show Menubar".

I finally find my way:

• first enable shortcut accelerators;

• then you can add, change or remove shortcut by pointing the mouse pointer on action in menu you wish to modify and tape the shortcut or backspace to delete it.