Collaboration allows two or more users to work on a document together.
With a shared document open, any user with read/write access can take control and edit the document. When the document is saved, all other users with the document open will immediately see the saved changes.
Collaboration is managed from the Sharing tab in the Panel.
You can easily see who controls a document by viewing the Traffic icon at the top of your document.
If it is green, you have control.
If it is red, another person has control.
Yellow means, please wait as control is being transferred.
If the Traffic icon is half green and half red, nobody currently controls the document.