This is an Fl_Group that creates a "flippy triangle" interface for
its children. Best used inside an Fl_Scroll.
Keyboard arrow keys can be used to move up and down through, open, and close the children.
Creates a new Fl_Flippy widget using the given position, size, and label string.
Set and get the open status of child by index or widget.
Set and get the index of the last child handled. If selectionIsShown() is true, this child's flippy-triangle area is drawn in the selection color.
Set and get whether the last-touched child's triangle is drawn in the selection color.