[1.12] Can't break custom fire/Doesn't burn

In my mod i have a block that is a custom fire, wich class is just this

 
	public class BlockFireMW extends BlockFire{
    public BlockFireMW() {
        super();
    }
}

Nothing special. But in game i got 2 main problems. The first is that i can't break it. If i click on it to "break" or ignite, it will break the block underneath instead of just ignite the fire (like vanilla fire does). The second one is that an entity walking on this fire will not burn or get damage. So how can i fix those since in the main class i didn't found anything related to this?