function rowClicked(event)
        {
            if (itemId === this._editingId)
                return;
            console.assert(!this._editingId);
            this._editingId = validItemId;
            var listItem = this.itemForId(validItemId);
            listItem.classList.add("item-editing");
            var editElement = event.target.editElement || this._editInputElements.get(validItemId).get(this.columns()[0]);
            editElement.focus();
            if (editElement.select)
                editElement.select();
        }
@param {!Event} event
@this {WebInspector.EditableSettingsList}