This is used to create a component that acts as
a container to group a set of components. All these components are under
one component or can say one parent. So this can be useful when we want
to nest two or more components into one parent panelGrid column. If we
want to render two components without using this tag then these will be
rendered in separate columns. This component renders its all children
and count them as one component. So this fact of this tag can be useful
for us in the case where a component allows only one child component.The
program given below will make you clear this concept.
Rendered Output : In the above code we
have taken 4 components in footer facet component. We have used
panelGroup tag to render these 4 components in a single column. It
happened because colspan has been set to 3 i.e. no of columns.