[Trinidad] executing js during PPR

[Renzo Tomaselli]

Hi, I noticed a strong asymmetry while executing a js block included 
into a PPR target: on IE this runs once, in the context of _pprIFrame.
On FF it runs twice, once in the context of _pprIFrame and then in the 
context of the original page, after PPR modifications have been applied 
to the dom.
While on FF this behavior offers a full suite of tuning opportunities to 
play with PPR contents, on IE the game is severely constrained.
Is that a bug to hunt for, a side-effect or a wanted feature ?
Thanks,
-- Renzo