Set LastTabCaption to the caption of target controls when the control specified by the TabControl property is on its last page and the action can't tab beyond the last page. When the target page control is not on the last page, the caption for client controls is given by the Caption property. When the target page control is on the last page (and Wrap is false), TNextTab caches the original value of Caption and changes the Caption property to LastTabCaption. If the target page control returns to a previous page, TNextTab then restores the original value of the Caption property. 

LastTabCaption is designed for client controls such as the button in a tabbed dialog that changes from a "Next" button to a "Finish" button when the tabbed dialog reaches the last page. 

Caption 

TabControl 

Wrap