src/common/js/winjs/js/ui.js
function ItemEventsHandler_toggleItemSelection(itemIndex) {
                    var site = this._site,
                        selection = site.selection,
                        selected = selection._isIncluded(itemIndex);

                    if (site.selectionMode === _UI.SelectionMode.single) {
                        if (!selected) {
                            selection.set(itemIndex);
                        } else {
                            selection.clear();
                        }
                    } else {
                        if (!selected) {
                            selection.add(itemIndex);
                        } else {
                            selection.remove(itemIndex);
                        }
                    }
                }
function ItemEventsHandler_toggleItemSelection(itemIndex) {
                    var site = this._site,
                        selection = site.selection,
                        selected = selection._isIncluded(itemIndex);

                    if (site.selectionMode === _UI.SelectionMode.single) {
                        if (!selected) {
                            selection.set(itemIndex);
                        } else {
                            selection.clear();
                        }
                    } else {
                        if (!selected) {
                            selection.add(itemIndex);
                        } else {
                            selection.remove(itemIndex);
                        }
                    }
                }
function ItemEventsHandler_toggleItemSelection ( itemIndex ) { var site = this . _site , selection = site . selection , selected = selection . _isIncluded ( itemIndex ) ; if ( site . selectionMode === _UI . SelectionMode . single ) { if ( ! selected ) { selection . set ( itemIndex ) ; } else { selection . clear ( ) ; } } else { if ( ! selected ) { selection . add ( itemIndex ) ; } else { selection . remove ( itemIndex ) ; } } }
In single selection mode, in addition to itemIndex's selection state being toggled, all other items will become deselected
In single selection mode in addition to itemIndex s selection state being toggled all other items will become deselected