Responsive design in Perspective

I have inserted a background into a coordinate container, and above it I have inserted a container with data that is a position according to the background of the root container. The view from the Perspective launch window, if the window is resized proportionally then the child container resizes proportionally. However, if the window is deformed, that is to say, stretched window on one side only, then the child container deforms according to how much the window is stretched. The root container does not do this, so the data in the child container shifts even extending beyond the background I have incorporated into the root container.
I need the child container to resize proportionally with the background even if the window deforms on only one side.
This happens both in a flex container and coordinate container child.
The configuration of the "root container" is:

You need to set the aspect ratio if you don't want it to change. I bind it to the view's defaultSize width and height