Homepage: https://emacswiki.org/emacs/download/tooltip-help.el
Updated:
Show help as tooltip
F1 is a useless key on my keyboard, because I don't use it in Emacs, so I thought I bound some kind of help function on it. I thought some kind of help which is less intrusive than the default one (doesn't open a new window, frame, etc.) would be useful, so I made one using tooltips. When using in a Lisp program the tooltip is displayed without osbcuring the position of the cursor and it is dismissed automatically when the user continues typing, so it doesn't disrupt the current window configuration like the current help does. How it works: If the cursor is ON a symbol then help is shown for that symbol. If the cursor is after or before a symbol then the function symbol belonging to the containing sexp is used. If no such symbol is found then a nearby symbol is tried. If the symbol has both function and variable bindings then both of them are shown together in the tooltip. When function help is shown and the cursor is in the argument list then the relevant argument is highlighted in the documentation. (Using code copied from Emacs Wiki.) Support can be added by creating a function with a name like this: th--handler Currently only Emacs lisp mode is supported. Tested on Gnu Emacs 21.