Main work area (tabbed work area)

Clicking on any area heading in the left hand navigation panel will open it up in your main work area:

You'll notice that this opens up as a tab within the work area. Furthermore, any other areas will open up as additional tabs, and any record opened up from within an area will also open up as a new tab:

These can be closed individually when finished with or, if you have multiple tabs open, you can right click on any tab to close it, close all others apart from that one or close all tabs to the right of it.