this horror depends on unsigned max increment to wrap-around to 0

understandable dbgutil out of bounds iterator checking regression from

commit 3af368f0f8e6691aa2eef177ccfcfcb95885c84b
Date:   Tue Aug 14 21:03:04 2012 +0200
    AnimationWindow: convert List to std::vector

Change-Id: I8ff3e0726cc0d6e643f2f4e08b0ca41e327e5efc