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