Enable sidebar for blog post in Quark theme

I can't figure out, how to enable sidebars for blog posts in Grav with default Quark theme.
I have a "home" blog page with subpages for the individual post which works ok.
In the configuration for my mail blog page I have enabled "Show Sidebar" - but no sidebar shows up.
How do I enable the sidebar? Is there some settings I have overlooked?

That sounds right @gyldensaa- by default "Show Sidebar" is enabled by default, did the sidebar ever show for your blog home page and posts?

You could also download the Blog Site skeleton (which uses Quark) to verify how "Show Sidebar" works etc with the sample content.