Yes it throws an exception. I provided the code and version, you guys should run the 2 line code and see for yourself. Anyway the exception is:
ext-all-debug.js:3351 TypeError: 'undefined' is not a constructor (evaluating 'new prototype.configClass()')
This occurs in function 'extend'. I have (or had) a class which extends from Array. ExtJS throws exception in the extend function (see error message above). Also, this happens when the debugger is off. For some reason whenever I turn on debugging it works fine (reproduces 100% of the time).
How to reproduce:
Debugging should be *disabled* for this error to occur.
(If its on, turn it off in the debugger in Safari (bottom left corner in scripts tab) and run the above code.