The Editing Area uses different areas (like window panes) to separate the Editing functions. The three main panes each have their own purpose. An Editors actions usually flow from left to right across the panes.
For simplicity we call the three panes the Module Pane, Navigation Pane, and the Editing Pane.
The system and editing area require some settings in your browser to be available. Settings can usually be accessed by the Tools / Options menu