We seem to be going through that same phase right now with our 22 month old daughter. She has several "chairs"; a learning tower that stands by the kitchen counter where she often helps me bake/craft/etc... and has become her favorite place to stand, and as a result, she often has snacks or lunch there. She also has a new little wooden chair that sits in the living room, and we have let her eat in there at the coffee table for dinner with us on occasion as well. We prefer to have her in her high chair with us at the dining room table for dinner, and that is the case much of the time, but if the struggle gets to great, our thoughts are its not worth the fight. I understand that at her age, it is difficult to sit and focus on a meal for more than 10-15 minutes. And I guess I feel it more important that she eats, rather than "where" she eats.
I certainly don't want her to feel there are no rules for eating, as I grew up always sitting down to eat with my family and proper manners were expected. And I have worried about that with this new independence of choice that she is expressing, but I guess I guess I think that she has plenty of time to learn the rules when she is more able to control her impulses, and so for now, we will impose structure where we can, but also pick our battles- which means if it's a bif struggle and she is getting so worked up, its not worth it.
This morning for example, my husband was making breakfast for her before I went to work. She grabbed her yogurt container, and dad said he would put some in a bowl for her but she'd have to get in her chair (high chair) to eat it. She went into the living room, we thought to play for a few minutes. After noticing that she had been very quiet for 5-10 minutes, I peeked around the corner, and here she had pulled her little chair over to the coffee table, cleared off all of her toys,and was sitting there with her legs crossed, waiting so patiently for her yogurt. It just caught my heart, and I said to my husband, "Oh, sweetie, she has been sitting in her chair that whole time waiting so patiently for her breakfast". He said "Does she look cute?" I said yes. He said "Does she look cute enough that she can eat her yogurt in the living room this morning?" I said yes. And he brought her eggs and yogurt and a bib, and there they ate before I left for work. Sometimes I think it just makes her feel like a big girl to pull up her own chair, help to clear off the table, and she needs a little of that independence. She is able to sit down and be polite for big meals, for dinner, (most of the time), and for holidays or when we go out to eat. So, I think if you can give a little freedom in some areas you are more likely to get a little better cooperation on other areas! Sorry that this is so long, and hope this helps some! At least to know you are not alone!