The Layout widgets in Dojo are varied in nature, but their most common use is as 'windows' or areas which organize and present other widgets or information. Several use the same kind of child elements the ContentPane.

The ContentPane is a widget which can contain other widgets and plain HTML, reload content using Ajax and so on. The ContentPane can also be used stand-alone in a page, but is more usable inside a layout container of some sort.

And what is a layout container? Well, it's a widget which contains ContentPanes, of course. A layout container can often contain other widgets as well, but most containers work very well with a different configuration of ContentPanes, which properly insulates the further contents.

Take the TabContainer, for example. It is used to organize two or more ContentPanes, where each gets its own tab. When a user clicks on one of the tabs, the ContentPane inside it is shown and all others are hidden.

Using BorderManager can bring the necessary...