This reverts commit b90a8f63 because it
broke the wallpaper configuration.

quoting David Edmundson explaining the old behavior:

What the code was doing before:
 height is either:
   the size of the child items
   filling up all the way to the buttons at the bottom of the dialog

The problem it's trying to solve is we sometimes have content of
variable height in a scrollview; which needs to know the content height.
This is a bit of a loop logically.