Full width template

Good day

I am using the Sidebar / Content layout under theme options.
i only need the sidebar for certain pages on my website.

the full width template takes up the entire width as I like.

However if i create a new template with the same exact code from the full width template, it does not take up the entire width.

I suspect it is something to do with the name of the template “Full Width” that allows this? how do i add my other templates to behave in this manner?

much appreciation for any help

Thanks ^_^