Elisp manual omission?

[Nick Roberts]

This entry in the Emacs Lisp Reference Manual aroused my curiosity about
tooltips:

 - Command: delete-frame &optional frame force
     This function deletes the frame FRAME.  Unless FRAME is a tooltip,
     it first runs the hook `delete-frame-functions' (each function

So a tooltip is a frame. I wanted to find out more but there nothing much
about them. I expected to find a section in 'Emacs Display'. Is this a
deliberate omission?


Nick