A 
gtk-stack-sidebar widget enables you to quickly and easily provide
    a consistent "sidebar" object for your user interface.    
  In order to use a 
gtk-stack-sidebar widget, you simply use a  
gtk-stack widget to organize your UI flow, and add the sidebar to your  sidebar area. You can use the 
gtk-stack-sidebar-stack slot access  function to connect the 
gtk-stack-sidebar widget to the  
gtk-stack widget.  
CSS nodes
    The 
gtk-stack-sidebar implementation has a single CSS node with name    stacksidebar and 
.sidebar style class. When circumstances require it,    the 
gtk-stack-sidebar widget adds the 
.needs-attention style
    class to the widgets representing the stack pages.