Hi, I'm trying to do a little web browser in MacRuby. It's coming along nicely, but I'm having a strange problem with history. I set up a WebView and it loads, I go to a few urls, then call the back action on the WebView. The first time I do this, I get the error below and get dumped to gdb. Terminating app due to uncaught exception 'WebKitThreadingException', reason: 'void -[WebHistoryItem finalize](WebHistoryItem*, objc_selector*) was called from a secondary thread' If I type quit in gdb, it detaches from the debugger and continues. From that point I can call goBack and goForward and they work fine. Now I guess I've got two ways out of this: 1. Figure out why WebHistoryItem.finalize is being called from another thread, or 2. Add some kind of exception handling to catch this error and ignore it. I haven't really had any luck with 1, so I tried 2 (using http://www.macdevcenter.com/pub/a/mac/2007/07/31/understanding-exceptions-an...) but I couldn't get it working in MacRuby. Can anybody point me to a way to catch uncaught exceptions in a MacRuby program? Thanks, Brad