bug#14793: 23.4; Cannot bind a function to a sequence of two mouse keys

[Alex]

Eli, do you know how to solve this?

Try this:

(define-prefix-command 'test)
(global-set-key (kbd "C-t") #'test)
(global-set-key [mouse-3] #'test)
(global-set-key (kbd "C-t <mouse-2>") #'backward-word)
(global-set-key [mouse-3 mouse-2] #'backward-word)

Hitting C-t mouse-2 calls `backward-word' as intended, but hitting
mouse-3 mouse-2 displays an "Empty menu" error as in the original
report.

The error is thrown from Fx_popup_menu and is called from
read_char_x_menu_prompt, which is only called in the mouse case. I'm not
sure how to proceed from here.