bug#53170: 29.0.50; Can't repetitively click next node button inside Info header line

[Eli Zaretskii]

> From: Juri Linkov <juri@linkov.net>
> Cc: luangruo@yahoo.com,  53170@debbugs.gnu.org
> Date: Tue, 11 Jan 2022 21:12:50 +0200
> 
> >> The second click selects the word.
> >
> > Why is it useful to select the word on the header line?
> 
> Sorry, I missed that this report is about the header line,
> I thought it's about breadcrumbs.
> 
> Then these bindings are interfering:
> 
>     (define-key keymap [header-line down-mouse-1] 'mouse-drag-header-line)
>     (define-key keymap [header-line mouse-1] 'mouse-select-window)
> 
> The problem can be fixed by replacing these lines with:
> 
>     (define-key keymap [header-line mouse-1] 'Info-mouse-follow-link)
> 
> But I don't know how important is the feature of selecting/dragging the 
> header-line?

I don't think I understand how 2 clicks one after another are taken as
a drag-mouse event.  Can you tell why this happens?