bug#56198: Request to delete window with mouse event

[Tak Kunihiro]

> I frequently split my windows,  I usually kill the buffer using the
> menu bar.  But this leaves me with the window open with some other
> buffer.  Would like to request some facility to delete a window
> (delete-window) using the mouse, as I frequently do for `kill-buffer'.
>  Perhaps the capability could be inserted in the window mode-line. 
> Where one can usually turn off a minor-mode with the mouse.

How about having `Close' in context menu?

["Close"
    (lambda () (interactive)
      (if (one-window-p)
          (if (> (length (visible-frame-list)) 1)
              (call-interactively 'delete-frame)
            (kill-buffer (window-buffer))) ; (quit-window)
        (delete-window)))
    :help "Remove this window or this frame, or kill this buffer"
    :visible (not (region-active-p))
    :active t]