Car radio won't turn off after the ignition is off and key pulled out?

I have a 2008 Honda Accord and just recntly realized that the car radio stays on after the car is completely off. I turned the radio off manually but the led display still stays on. It has the factory radio. I also just got a new battery 2 days ago. Help please, what could it be and how do I fix it?

Stuck relay contacts. Find the main relay box (SOMETIMES NEXT TO THE FUSE BOX) give it a good tap to each of the relays (cube looking black/transparent things).
If you can't turn the radio off even manually, then the problem could be in the radio system's circuit.