Steps to reproduce

set showtabline=0 showtabpanel=1 tabpanelopt=vert
set fillchars+=tpl_vert:│

1. :tabnew
2. :e ~/.vimrc
3. :vs
4. :tabonly

Expected behaviour

Tabpanel should be closed and no ghost screen estate should appear on the right side.

Version of Vim

9.1.1392

Environment

debian12, bash

Logs and stack traces