Delete window when the last tab buried.

tab-line-close-tab-function.el

(setq tab-line-close-tab-function
	#'(lambda (tab)
	    "Delete window when the last tab buried."
	    (let* ((buffer (if (bufferp tab) tab (cdr (assq 'buffer tab))))
		   (window (get-buffer-window buffer)))
	      (with-selected-window (or window (selected-window))
		(let ((last-tab-p (length< (tab-line-tabs-window-buffers) 2)))
		  (if (eq buffer (current-buffer))
		      (bury-buffer)
		    (set-window-prev-buffers nil (assq-delete-all buffer (window-prev-buffers)))
		    (set-window-next-buffers nil (delq buffer (window-next-buffers))))
		  (when last-tab-p
		    (ignore-errors (delete-window window))))))))