The overview bar is displayed above the waveform in each editor and helps you navigate the waveform.
You can toggle the overview bar by choosing View > Show Overview/Hide Overview.
The full waveform is displayed in the overview bar.
The unshaded portion of the waveform display represents the portion of the waveform shown in the editor. You can drag this portion to navigate the waveform.
The current selection is also represented in the overview bar.
To navigate the waveform, you can drag the unshaded portion of the waveform display:
To zoom horizontally, you can drag the ends of the unshaded portion of the waveform display: