function _clearMessagePopover() {
            if (self._$messagePopover && self._$messagePopover.length > 0) {
                // self._$messagePopover.remove() is done by PopUpManager
                self._$messagePopover = null;
            }
            _removeListeners();
        }
Display temporary popover message at current cursor position. Display message above
cursor if space allows, otherwise below.

@param {string} errorMsg Error message to display