Keyboard works well but mouse buttons not detected so far. For me the ability to use older usb keyboard is priceless. Thanks !
To the developer, When connected with computer USB port, it was okay, BTW, it was also worked only for seconds and disconnected with portable battery(5V), so it's inconvenient for me to use it continuously. Sincerely.
Temporary powered-on problem was solved by another LED-equipped hub attached with my portable powerbank, i.e., Bluetooth Adapter > USB hub > Power bank