Revert "Do not render background when mochigoma is dragged"
Revert "Do not render background when mochigoma is dragged"

In fact, this change has no meaning. We need anothor solution.

This reverts commit 00bc0e33af11ebc6e6793a1f91cfc84bf41340fa.

orangain/kifu-notebook,orangain/kifu-notebook,orangain/kifu-notebook,orangain/kifu-notebook,orangain/kifu-notebook