bug#49247: 28.0.50; [Feature Request] Make tab-bar-lines dragable

[Eli Zaretskii]

> Cc: juri@linkov.net, 49247@debbugs.gnu.org, s930054123yaoyao@gmail.com
> From: martin rudalics <rudalics@gmx.at>
> Date: Thu, 1 Jul 2021 09:53:12 +0200
> 
>  >> See section 30.4.3.7 Mouse Dragging Parameters of the Elisp manual.
>  >
>  > Thanks.
>  >
>  > So you are saying that the original problem already has a solution?
> 
> What is the original problem?

Quoting from the original report:

  As title. I think this might be useful for people who disable the
  external border and use tab-bar as their status bar. I found there
  is option to move the frame by draging header-line (the
  drag-with-header-line frame parameter), so I think it's reasonable
  to also support something like "drag-with-tab-bar-line" for
  tab-bar-mode users.

You explained that it is possible to drag such frames by the mode line
of the bottommost window, which provides solution for frames that have
no header line.