Aha… with the scene set to scale width/height — yes that is true!
I find that behaviour useful actually.
You could for instance do a smartphone layout, eg. 320px wide. Add an image with a transparent background, center the image — and more parts of the image will be visible when the scene is wider than 320 px.
I have used it myself. In my case it is a blurred, fading shadow of an object that gets more revealed at a larger width. Looks very cool. Sorry didn't think of that when I replied…