Okay, I've found them, the arrow and the battle textbox. I've clearly done with the text box. But, when I was working for the battle textbox, then used NSE to import and repoint everything related to the textbox, the game glitches everything. Well, I have backups so this doesn't make any threat to me.
Well, I tried your expansion things about battle backgrounds. To view the 21th background, should I set the Var 0x40F7 0x20 in the map script on A-Map? Am I right?
How many screenshots should I have to post my hack? Well, I've just put the post in my visitor message for a while. See it for yourself in my profile. If the post is valid, I'll post it on the Hacks Studio and confirm it later. I think that you are the ones who confirms the post or not.