This is a theme bug with no effect on Irssi's functionality.

I have recently been checking out Irssi's default-installed alternative colorless theme as an alternative to default theme. However, as soon as I applied it to my horizontally-split Irssi session; I found that the theme does not correctly (de)color the vertical window split bar; which starkly contrasted with the rest of window.

This is more-or-less trivial to fix (with caveat), pull request will follow.

Exact Steps to Reproduce

1. Run irssi --noconnect

2. Issue command: /set theme colorless

3. Issue command: /quit

4. Run irssi --noconnect

5. Issue command: /window new -right split

6. Issue command: /1

7. You would see that vertical window split bar is not colorless, which is against the point of using colorless theme...

   

Side Notes

• My terminal's default foreground/background color combo is #FFFCDA/#000000.
• This is not the only problem I found in stock colorless theme, other notable one is the lack of messages' bold highlights in several places.

System Information

Irssi: 1.2.2 (20190829 0225)
System: Fedora 32 (GNU/Linux x86_64)