When I change line graphics mode by pressing ~, the status line reports the change:

However, if I actually try to use this configuration command, either directly in the app (via :set main-view-line-graphics = …) or via a config line in .tigrc, I'm given the error message Failed to parse view column type: …:

Instead, I'm able to get this working by setting the config key line-graphics, but as a very casual user I don't know if I'm intended to be able to do it both ways.