What happened to the separation lines?

I cannot remember what the feature was called, but it enabled you to make a horizontl line to separate things. It allowed you to designate how log and whether or not you wanted a shadow.

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It separated text areas as I am demonstrating with the line above.
How do I get it back? There is an option to make a space. I like that, but I also want to be able to creat that line.

Thanks

https://wordpress.org/plugins/tinymce-advanced/