Your pasar malam probably fake mercury case? I'm using mercury case too and I don't have the problem you're describing. Also what brand is your screen protector? I'm using SGP ultra crystal, probably your screen protector is reused therefore not as sticky?

I tried Zenus Air Jacket Casing, casemate toughcase, SGP Neo Hybrid and finally Mercury.. though Mercury is the cheapest among all it's my favourite, with Neo Hybrid comes as second but I don't recommend neo hybrid cuz over time the black rubber at the back of camera will become loose due to the heat of our phone. Toughcase is for those clumsy people who drop their phone a lot and it offers best protection for the price of thickness (sibeh thick till beh tahan), zenus air jacket never cover the front part doesn't feel secure coz phone can always come out from the casing.

Oh and i bought my mercury from ebay, rm25 including shipping from korea bought two colors so can change here change there wahaha

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Added on December 9, 2011, 9:48 amthe new 10 cents apps macam boring sia..

Samsung galaxy s2 I9100
1.2Ghz dual core Exynox 4210.
Overheat easily.(Fixed with Android 2.3.5)
Poor battery life. (Fixed with Android 2.3.5)
Fully run at 1.2 GHz CPU.
So far no apps/ games compatibility issue reported.
Better 3D performance.
Lot of custom firmware, kernel, modification, tweaks.
Normal text font in PAPAGO.
Perform better and less lag while browsing the Internet and score better when opening apps/multi tasking.

Samsung galaxy s2 I9100G
1.2Ghz dual core TI OMAP4430.
Doesn’t overheat easily.
Better battery life.
CPU capped at 1008 MHz.
Might have more apps/ games compatibility issue.Some games developed for GT-I9100 like Asphalt 6 can’t be launch on it.
Poorer 3D performance.
Not much custom firmware / modification.
Very small fonts size in PAPAGO
Might feel lag when opening up too many app compare to GT-I9100 model.
Freezing alot