Kartik GridView Layout

I’m hoping someone can help me setting up the layout of the Kartik GridView. I’ve tried changing the value, but it doesn’t seem to make any change to the rendered output?

I’ve tried
'layout' => "{toolbar}{summary}\n{pager}\n{items}\n{pager}",

am I doing something wrong?

I’ve tried other layout, for instance
'layout' => "{items}",

and no matter what I use, the rendered output is always the same and doesn’t seem to care about what I ask of it.

Would anyone know what I am doing wrong here?

Thank you.