OK, bug report has been sent from my phone.  Thanks.

I sure wish someone at Xiaalive would at least acknowlege my comments.  Have you absolutely no suggestions as to what might be causing the problem?

Further information:
If I disable screen rotation from the phone's menu
(SETTINGS > SYSTEM SETTINGS > DISPLAY > uncheck AUTO-ROTATE SCREEN)
then the app works reliably as it is supposed to with no disappearing acts, even though it remains in portrait mode.

Your response would be appreciated. Thanks.