The active state of a state, regardless of its logic sense.
![[index]](../images/index.gif)
![[Contents]](../images/toc_d.gif)
![[Help]](../images/help_d.gif)
![[Retrace]](../images/retrace_d.gif)
![[browse <]](../images/prev.gif)
![[Browse >]](../images/next.gif)