Quick Access Toolbar
The Quick Access Toolbar located in the top left corner of the AVS Audio Converter Main Window is a customizable tool allowing you to get quick access to the most frequently used functions of the software.
Left-clicking the arrow 
to the right of the toolbar will display the Customize Quick Access Toolbar menu (see the image to the left).
Tick/untick the Customize Quick Access Toolbar menu elements to show/hide them on the toolbar.
Adding/Removing Elements from the Toolbar
You can add/remove elements from the Quick Access toolbar. To add an element to the toolbar, right-click the desired command button on the ribbon command bar and select Add to Quick Access Toolbar:
To remove an element from the Quick Access toolbar right-click it and select Remove from Quick Access Toolbar:
