it won't let me put egg movement on a pokemon

[Darkness918]

help i cant put an egg move on a competitive chansey that im creating whit PKHeX if i put the egg movement in the relearn moves section the same as at the top, no matter what space i put it in it, it doesnt let me legalize it...

[Nuren]

Order matters.  The game first assigns default moves and adding egg moves at the end pushes the early ones off.