An example of the frozen background on a overflow box is seen in this Test Case by Gérard Talbot. Just scroll.
Failed: Opera 9.10~9.50 (bottom margin is missing)
Passed: Gecko 1.8~1.9 & Opera 9.50
Failed: IE 8 (background image on container gets frozen)
Failed: Opera 9.10~9.50 (bottom margin is missing)
Failed: IE 8 (background image on container gets frozen or non scrollable)
Passed: Gecko 1.8~1.9 & Opera 9.50
Failed: Safari 3 (Inner box should not be scrollable)
Failed: Opera 9.10~9.50 (bottom margin is missing)
Failed: IE 8 (background image on container gets frozen or non scrollable)
Passed: Gecko 1.8~1.9 & Opera 9.10~9.50
Failed: IE 8 (background image on container gets frozen)
Note: Gecko 1.8 will show the margin on both sides of the inner box.
Passed: Gecko 1.8~1.9 & Opera 9.10~9.50
Failed: Opera 9.10~9.50 (bottom margin is missing)
Failed: IE 8 (background image on container gets frozen)
Passed: Gecko 1.8~1.9 & Opera 9.50
Failed: IE 8 (container is non scrollable)
Failed: IE 8 (container is non scrollable)
Note: Gecko 1.8 will show the margin on both sides of the inner box and padding on both sides of the overflow box.
Failed: IE 8 (container is non scrollable)
Passed: Gecko 1.8~1.9 & Opera 9.50
Failed: IE 8 (container is non scrollable)