bug#70086: Mouse clicks in tab-bar don't call commands bound in keymap properties

[Adam Porter <adam@alphapapa.net>]

Hi Juri,

On 3/30/24 13:16, Juri Linkov wrote:
>> In my listen.el package on GNU ELPA, I'm trying to make mouse clicks in the
>> `global-mode-string' construct work when `mode-line-misc-info' is shown in
>> the tab-bar by including `tab-bar-format-global' in `tab-bar-format'.  I'm
>> including this construct in the `global-mode-string':
>>
>>
>>    `(listen-mode (:propertize listen-mode-lighter
>>                               keymap ,listen-mode-lighter-map))
> 
> Thanks for the request.  If possible could you send a minimal test case
> to see what exactly do you need.

Sure, the following code in a clean Emacs config seems to demonstrate 
the problem:

   (require 'cl-lib)

   (defvar tab-bar-ecm-keymap
     (let ((map (make-sparse-keymap)))
       (define-key map [tab-bar mouse-1] (lambda (&rest _)
                                           (interactive)
                                           (message "tab-bar-ecm-lighter 
clicked with mouse-1")))
       map))

   (defvar tab-bar-ecm-lighter "TAB-BAR-ECM-LIGHTER")

   (define-minor-mode tab-bar-ecm-mode "DOCSTRING"
     :global t
     (let ((lighter `(tab-bar-ecm-mode
                      (:propertize tab-bar-ecm-lighter keymap 
,tab-bar-ecm-keymap))))
       (if tab-bar-ecm-mode
           (progn
             (cl-pushnew lighter global-mode-string :test #'equal)
             (unless (memq 'tab-bar-format-global tab-bar-format)
               (cl-callf append tab-bar-format '(tab-bar-format-global))))
         (cl-callf2 remove lighter global-mode-string))))

Evaluate that code and then enable `tab-bar-mode' and 
`tab-bar-ecm-mode'.  Then you can see that "C-h k" followed by a click 
on the "TAB-BAR-ECM-LIGHTER" text in the tab-bar shows that the 
anonymous command is bound to that sequence, yet clicking the text 
doesn't call it.

> And the same should work on `tab-line-format' as well.

I haven't tried that, but sure, sounds good to me.  :)

> Indeed, events on the tab-bar have a different design where
> `tab-bar--event-to-item' should be used to get a bound command.
> You can see an example in `tab-bar-mouse-down-1' that uses
> (if (functionp (nth 1 item)) (call-interactively (nth 1 item))
> to call an arbitrary command.

I see, thanks.

--Adam