Hello!
Thanks for your replies!
Yes, I tried to run my app in debug (legacy) and debug (rapid) mode and pressing "Connect" button did not help.
So what I did afterwards:
1. Connected tablet via USB cable with PC
2. Enabled "USB Debugging" on tablet
3. Run "adb.exe devices"
4. Tablet returned a long string keeping characters (so I think, that I was connected with tablet?!)
5. Tried to load app via B4A GUI to tablet (ALT+F5) -> failed
6. Since debugging over USB cable failed, I switched back to B4A-bridge mode and – what a funny thing – I could see all Logs on the B4A GUI.
Actually I do not know what I have changed on my system, but it is working very well.