ExtActns

Add TPreviousTab to an action list to allow users to move to the prior page of a page control using menu items or toolbar buttons. Controls such as menu items and tool buttons linked to this action cause the application change the current page of a page control to the previous one. Typically, these client controls are the "Prior" button or menu item in a tabbed dialog. 

Before you can use TPreviousTab, you must assign a target tab control as the value of the TabControl property. Once the target tab control is assigned, TPreviousTab automatically disables itself if the target control is not enabled or if it is on the first page and wrapping is not permitted. 

TNextTab 

TPageControl 

TTabControl