i think doublespend not fix yet.
From the MultiBit FAQ I linked above:
Can you explain "doublespends" ?
That is where you get to spend the same money twice with different people. It was a common problem with digital money before Bitcoin solved it.
It's still possible to double-spend. However, it's much harder to do so, since the miners will not accept it. Unless you control the miner of course, then you could theoretically make it go through.
I wish people would stop complaining about double spends. IT never happens but people make out like it's a massive flaw and they're never gonna get their money.