Contour Shuttle has no Alt/h. Nevertheless, its help page can be requested by simultaneously pressing both Alt keys (left and right) on the keyboard followed by pressing any button on the Contour Shuttle. Here, pressing both Alt keys is necessary due to the way X11 tracks the status of modifiers. To cancel this mode, press any single modifier key (Alt, Ctrl or Shift) once. Note that the manual Shuttle Configuration will be the default one, rather than the one that you may have redefined.
The CINELERRA-GG Community, 2021