When Windows 8.1 was re-installed to Onda V891w and run Windows Update, sometimes touch device had un-expected situation that can’t be controlled.
be careful to update the touch driver which is “KMDF HID Minidriver for Touch I2C Device”. after update the driver, Tablet PC seems to had issue.
So far, I couldn’t find any resolution. so need to re-install Windows 8.1 again.