onLowOrRaiseHandStatusChanged never triggered

Is there a bug in window SDK? I am using the latest WIndow SDK zoom-sdk-windows-5.10.3.4884.
But it does not matter which versions. I tried every single older version of window SDK, none of the versions works period. I tried all the back to this version of sdk zoom-sdk-windows-5.9.1.2625.

I am testing to see if I can use onLowOrRaiseHandStatusChanged(bool bLow, unsigned int userid) callback function. But it never triggered.

Here is my codes:

  1. First I add the following function declaration of code to file “LoggedIn_sdk_controller_ui.h”
    virtual void onLowOrRaiseHandStatusChanged(bool bLow, unsigned int userid);

  2. Second I add this following function to file “LoggedIn_sdk_controller_ui.cpp”

    void CSDKLoggedInUIMgr::onLowOrRaiseHandStatusChanged(bool bLow, unsigned int userid)
    {
    wstring wstrMsg = _T(“SomeOne Reaised Hand”);
    ::MessageBox(NULL, wstrMsg.c_str(), _T(“Notify Msg”), MB_OK);
    }

I set up a break point at second line of this function, but it never hit when I toggle Raise Hand and Low Hand through another devices or on the SDK machine. But it does not matter from which device I toggled hand.

BTW I am running Zoom Default UI mode.

What else do I miss?

Any suggestion?

Thanks