Okay, here's my first thought. Who's the grown up in the family....
She is going to start right away with wanting to get up and wander around while eating.
She is going to drop food everywhere she goes.
She is at more risk for choking and dying when up walking around while eating. This is a carved in stone rule in child care. Kids are not allowed to leave the table at all when they are eating.
So, if you give in to her now not only are you setting a precedence that she is the boss and a temper tantrum will get her whatever she wants you are also teaching her that she does not have to learn to deal with frustration and learn coping skills.
That's what I see when the battle of the wills start. You need to decide what is more important. This is a little battle. She is going to eventually eat and forget she wants down. She still needs to eat and I would work towards that by keeping her in the high chair, even having a huge temper tantrum, until dinner is over. Engage her in conversation, play with her in small ways to distract her from the pressure. But don't give in and let her down until after you and hubby are done with your meal. Then decide what you are going to do to get her to eat. She needs to eat, I would never let her down again until you are ready to battle about staying seated during the meal.