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

[martin rudalics]

>> 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.

I've tried to implement now what the OP wanted - the parameter is called
`drag-with-tab-line'.

martin