This page demonstrates the use of re-entrant calls that cause Opera 10.50+ to strip the apply property from a function. (I don't know if other properties are stripped.) This happens only after the first test iteration. This does not happen in earlier versions of Opera, or any other browser.

In the second run, call.callable.apply(null, []); will throw an error

	Uncaught exception: TypeError: 'call.callable.apply' is not a function

while changing that to call.callable(); makes it work fine. call.callable.call(null); works as well.

I tested Opera 10.50 build 3296, Opera 10.53 build 3374, and prerelease Opera 10.60 build 3409 on Windows XP SP3.

Update: this was fixed in Opera 11.00 beta.