This is a weird niche bug which I’m documenting here in case I need it in future.
I have only seen it occur on a Samsung Galaxy S2 but I’m guessing it probably happens on any 2.x Samsung device running TouchWiz (it doesn’t happen on the Nexus S)
Steps to reproduce:
Create an activity with an ExpandableListView and set the childDivider property of the ExpandableListView to any colour, say red for ease of viewing
<ExpandableListView android:id="@+id/pageBundles" android:layout_width="fill_parent" android:layout_height="fill_parent" android:childDivider="@color/red" android:cacheColorHint="@color/white"/>
Now if you scroll the list for a while, particularly if you sort of wiggle it up and down quickly and then let it go the list will be completely covered by a solid block of the colour specified in the childDivider property. This will remain for a few seconds and then disappear.
To fix this issue just remove the childDivider property setting