General

The Page Options will automatically detect whether you have enabled or disable Elementor Page Builder.

Elementor Page Builder (Disabled)

When Elementor is Disabled you will have the option to set your Sidebar Layout and use the Sidebar Selection to choose which Widgetized Sidebar to use.

The Default Setting will inherit what you set in the Theme Options.

Elementor Page Builder (Enabled)

When Elementor is Enabled you will want to use the Page Builder to choose the sidebar layout and use the Sidebar element to add a sidebar selection.