WowAce

What steps will reproduce the problem?
1. Open WoW in windowed mode
2. I have the bars set up in "two bars wide" setup, i.e. two action bars side-by-side on the bottom.
3. Set up the two bars flush to each other. Then resize the window.

What is the expected output? What do you see instead?
I'd like the two bars to keep the same relative distance to each other when the screen is shrunk or stretched, but it instead moves them around. So if I set the two bars right next to each other, then make the screen smaller, they move into each other, so that one is on top of the other.  I'd like to point out that this doesn't always happen. For example, if I use one of the presets, the "two bars wide" one, this does not occur. But, if I resize the action bars (I like them to be 0.85 scale), then move them back, this bug recurs.

What version of the product are you using?
4.4.16

Do you have an error log of what happened?
Nope

Please provide any additional information below.

This is working as intended. You cannot keep UI positions constant when the size of the UI changes.

This should work fine however if you keep a constant UIScale and not let the game compute it.