in components/js/selectionModel.ts [162:170]
private get isColumnSelectionCurrently(): boolean {
return this._ranges
&& this._ranges.length > 0
&& this._ranges.find(r => {
let startAtFirstRow = r.fromRow === 0;
let endAtLastRow = r.toRow === Math.max(0, this._grid.getDataLength() - 1);
return !startAtFirstRow || !endAtLastRow || r.fromCell !== r.toCell;
}) === undefined;
}