If no modules are published to a position, the entire area or row will not appear/collapse.
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If no modules are published to a position, the entire area or row will not appear/collapse.
Configure at Admin → Extensions → Template Manager → rt_kirigami, then go to Layouts tab and set the varying Mainbody/Sidebar layout possibilities.
Note: If no modules are assigned to the Sidebar positions, the Mainbody will become full width.