fnUpdateThemeInverted = function (oThis) {
                var sParam = "sapUiUx3ToolPopupInverted";

                sParam = Parameters.get({
                    name: sParam,
                    callback: function (_sParam) {
                        oThis._bThemeInverted = sParam === "true";
                        oThis.invalidate();
                    }
                }) || "true";

                oThis._bThemeInverted = sParam === "true";
            }
This updates the instance's parameter if the ToolPopup is inverted per default

@private