page background sticks in .page-header while .content page background rolls

[rudolph9]

During the animation of the .top-bar collapse the root-level-background within the .page-header sticks to the container, while the root-level-background within the .content rolls under the the container.

To be more clear, the the background on the container .page-header and .content are set with a low opacity such that the container under the according containers is showing through, and in the case of testing the root-level-background.