On a layout you could have different parts. Almost all things are possible to control on each part but there is one things that is impossible to control that makes the UX (user experience) bad especially running on a device (tablet/mobile phone).
In layout mode it could look like this
After I then go to Browse Mode it looks like this all my parts like I want them to do.
Now when I am scrolling down my Body Part is stretched out and that white are is nowhere to control.
As you can see, the white area stretch out and there is no way for me to control that. I would like background for that part to behave like I have setup in Inspector with the grey color part.