Mother-In-Law calling my Son the name she prefers

Hannah

So I just had my second child, a boy, who we named Abram Jack. He goes by Abram. My mother-in-law insists on calling him Abram Jack "because she's always loved the named Jack" BUT I also know when we were talking names she hated the name Abram. I'm annoyed she won't just call him Abram like everyone else because it makes me feel like she hates his first name. Am I overreacting? Should I just let it go? There is a power struggle between her and I sometimes, so I feel it necessary to put my foot down in certain situations. Should this be one of them?