GroupFooterItem

Represents a group footer item in the Grid.

Name	Type	Default	Description
data	GroupResult		Holds the group data.
group	GroupItem		Holds the current footer group item.
groupIndex	string		Sets the index of the group item.
level	number		Sets the nesting level of the group. The root group is at level 0.
type	"footer"		Sets the type of the Grid item.