Created attachment 643386 [details] black screen with visual artifact When loading a page, pancake displays a jarring black background, sometimes with visual artifacts or parts of sprites that should be hidden. You can trigger this by logging out, or hitting on the settings menu, or when the search page loads the home page after crossing out a search.
it displays the black background for a split second until the intended background is loaded.
We have also seen it happen in the Account menu.
Both on iOS 5.1 and iOS 6.0b3.
I believe this was related to memory/hardware acceleration issues due to #770634. We're going to avoid the animation on Top Stacks for now so we can wrap up and ship. Please re-open if you continue to see these issues in default.