Runaway kids living inside a mall?

I searched through the entries tagged for childrens and ya genres and didn't see anything like this:

I remember reading a book sometime between 1989-1993 about a girl, and possibly her brother, who ran away or were orphaned, or were locked in accidentally -- at any rate, they ended up living inside a shopping mall, with several other kids. The kids were all given nicknames. I remember specifically a girl who was called Julia, after Julia Child, because she was in charge of getting food from the cafeteria/food court. I wish I could remember anything else, but that's really it!

I had checked this out from my library, but looking through the online catalog didn't turn up anything that seemed familiar. Neither did several keyword searches on Amazon and Google. I think this was in the children's (junior fiction) rather than the Young Adult section, if that helps any.

I did read a lot of Richard Peck, but I'm pretty sure this was NOT The Secrets of the Shopping Mall, as the mannequins from that book don't sound familiar. My memory of this is so spotty though I could be wrong. For a second I thought it could be Kay Reed's The Night Children, till I realized that was published only last year.

I've been vaguely recalling several books from my childhood lately, and this is the only one I can't seem to find again! Many thanks for suggestions, or for confirmation if this is indeed the Peck book.


*ETA: It sounds like from various comments that I am in fact thinking of Secrets of the Shopping Mall! Thanks to everyone for commenting, and so quickly!
This sounds really familar, but I'm thinking of something slightly different.

I remember reading a book where I believe it was 3 kids, an older sister with 2 younger siblings, and I think they were in the car with their mom. She goes to the mall telling them to wait in the car and she would be back soon but never does. They waited a long time for her and got hungry so they went into the mall and the older sister bought them lunch in the food court with the little money she has. Eventually they become orphans somehow. I can't remember much else. I want to say there was also a part where they were in the woods but I might be getting that mixed up with something else. Is this the story you are thinking of?

At first I thought it was The Pinballs, but I looked it up and it doesn't seem to be the same one. Even if I'm thinking of a different book than you, I'm wondering what mine is now. Heh.
The book you're thinking of is "Homecoming" by Cynthia Voigt

OP, that sounds like a mix between "The Girl Who Owned a City" and "From the Mixed-Up Files of Mrs. Basil E. Frankweiler." I'd be interested to read it.
Yeah, I thought of Mixed Up Files, but it's only the two kids (brother and sister), and it is in a museum.
The one like this that I looked for and found a couple of years ago was the Peck. :) Interesting if there's another one out there from the same era!
My first thought was the Peck book. The "mannequins" in that book aren't really mannequins, they're children hiding out in the various stores. The first one they encounter is a girl pretending to be a mannequin.

A couple of things I remember from that book are the girl having her clothes changed by one of the clerks (and she was supposed to go up to meet "mummy in Better Dresses" to pay for them-- there being no "mummy in Better Dresses," of course she didn't). I believe there was also a girl hiding inside one of the boxes near the glassware-- Crystal? I don't recall Julia offhand, but it wouldn't shock me; I think the names the other children used depended on the specific place they were hiding. (Thus Crystal.)

It's been a long time since I read it, but does this make it sound more or less like the book you're looking for?
This does actually sound like it's probably the same book. I think the blurb given on Amazon says something about "a mannequin coming to life", so your description of it makes more sense. Thanks for commenting!
I think it's the Peck book. All the kids had different nicknames based on the dept they "hid" in. In fact, they weren't allowed to refer to each other by their "real" names.