Panel: Adjusted CSS for dismiss modal. Fixes #6640.
Panel: Removed superfluous selector.

The page container doesn't get the animate class. We don't need to 3D
the whole thing.
Panel: Cleanup comments.
Panel: Removed overflow setting for active page now the page can't be moved anymore.

This reverts the change made by commit b622d0a. It is no longer needed
after 651610a.
Demos: Typo fix.