How does the status bar within the news overview work?

Publishing of a post is deactivated or has ended

The bar is greyed out.

A post is saved as a concept or a draft

The status bar changes to purple.

A post is active

The bar turns partly green. 

The closer the post approached the end date of the post the more greyed out the bar will get.

A post has been scheduled

The bar gets (partly) orange.
The closer the post approaches the publishing date of the post, the more greyed out the bar will get.
On the publishing date, it finally will turn green.

A post is published forever

The bar will stay green.

If you hover over the bar with the mouse, you will see more detailed information.