In Everquest II (EQ2) when you press a target key like F2, the first time it targets the player, the second time it targets this pet.  This can cause confusion to the Boxin Assistant and it can heal the pet instead of you and vice versa.  The old trick, which still works, and in other games, is to create 2 macros. One to target you, and one to target the pet like

• /target playername
• /target petname

Then use these as the heal target key instead of the group dropdown.  But in EQ2 there is a pretty much unknown command to turn this off:

/target_allow_pet_member_toggle 0

This turns off the pet toggle until you log out. We put it in our assist macro so we do not have to worry about it anymore. Works great