This problem drove me crazy for some long time and I thought that this is IDE problem, but at last found the right solution. In Mac, when you type after letter for example – “a”, the quote, no matter single or double it changes to á, a’ => á
When you type code, $a = ‘a’; it transforms to $a = á, and then you try to write quote after typing the string and so on, it’s so boring, believe me, if you came here 🙂
How to turn off. Go to System Preferences » Language & Text » Input Sources, check US keyboard and then uncheck International (you cannot uncheck US International, if other US keyboard not checked) and that’s all.