+;; This is taken from notmuch-wash: maybe it should be unified?
+(defun notmuch-show-toggle-part-invisibility (&optional button)
+ (interactive)
+ (let* ((button (or button (button-at (point))))
+ (overlay (button-get button 'overlay)))
+ (when overlay
+ (let* ((show (overlay-get overlay 'invisible))
+ (new-start (button-start button))
+ (button-label (button-get button :base-label))
+ (old-point (point))
+ (inhibit-read-only t))
+ (overlay-put overlay 'invisible (not show))
+ (goto-char new-start)
+ (insert "[ " button-label (if show " ]" " (hidden) ]"))
+ (let ((old-end (button-end button)))
+ (move-overlay button new-start (point))
+ (delete-region (point) old-end))
+ (goto-char (min old-point (1- (button-end button))))))))
+