To extend a panel on a cabinet, first click on the desired panel to select it. Next, select the Panel tab in the lefthand panel, and select the Construction icon at the top of the panel.
Then, select the Extension Parameters drop-down menu,
Depth Extension:
To extend the panel upwards or downwards (for vertical panels) or backwards and forwards (for horizontal panels), select the Depth Extension dropdown menu. and enter the desired extension length into the Bottom field(to extend the bottom edge of the panel) or Top field(to extend the Top edge of the panel).
Likewise, to recede a panel edge, type in the negative value of the desired distance, into either the Bottom or Top field, depending on the edge you wish to recede.
Width Extension:
To extend the panel leftwards or rightwards, select the Width Extension dropdown menu. and enter the desired extension length into the Left field(to extend the left edge of the panel) or Right field(to extend the Right edge of the panel).
Likewise, to recede a panel edge, type in the negative value of the desired distance, into either the Left or Right field, depending on the edge you wish to recede.