The area in which displays column sum cells like GridFooter under Grid Header.
It is used as summary property. Since it is be created internally when creating grid header, you do not need to directly create this class object.
grid.setOptions({
header: {
summary: {
visible: true,
styles: {
background: "#100088ff"
},
head: {
text: "\u03a3", // sigma
styles: {
fontItalic: true,
color: '#800'
}
}
}
}
});