I'm getting a repeated crash with WebKit. It seems to be related to a delay in loading XML into the main WebFrame: especially on the initial launch. The small XHTML loads quicker on subsequent new windows. If the window resigns key while the data is loading the crash occurs. Usually this load happens very quickly and so there's no time for the window to resign key while loading, but with my delay its happening more frequently. So I guess what's happening here is the WebCore FontFallback is trying to respond to a notification about a window resigning key and then query the WebView for information that's just not there (since the data's not finished loading). I'm not familiar enough with the WebKit codebase to understand much more than that. The crash log: #0 0x093145cc in WebCore::FontFallbackList::fontDataAt at FontFallbackList.cpp:60 #1 0x0926f830 in WebCore::Font::lineSpacing at Font.cpp:391 #2 0x091cf154 in WebCore::RenderObject::lineHeight at RenderObject.cpp:2541 #3 0x091bb60c in WebCore::RenderFlow::lineHeight at RenderFlow.cpp:298 #4 0x091984e8 in WebCore::RenderBlock::lineHeight at RenderBlock.cpp: 3248 #5 0x09194a10 in WebCore::RenderBlock::layoutInlineChildren at bidi.cpp:1751 #6 0x091a5394 in WebCore::RenderBlock::layoutBlock at RenderBlock.cpp: 487 #7 0x091a4cc8 in WebCore::RenderBlock::layoutBlockChildren at RenderObject.h:465 #8 0x091a53cc in WebCore::RenderBlock::layoutBlock at RenderBlock.cpp: 489 #9 0x091b0ab8 in WebCore::RenderView::layout at RenderView.cpp:117 #10 0x09104428 in WebCore::FrameView::layout at FrameView.cpp:473 #11 0x090e9408 in WebCore::Frame::setIsActive at Frame.cpp:3343 #12 0x9293fad8 in _nsnote_callback #13 0x90803010 in __CFXNotificationPost #14 0x907fb0ec in _CFXNotificationPostNotification #15 0x92929ee0 in -[NSNotificationCenter postNotificationName:object:userInfo:] #16 0x9374c95c in -[NSWindow becomeKeyWindow] #17 0x9374c138 in -[NSWindow _changeKeyAndMainLimitedOK:] #18 0x9374b288 in -[NSWindow makeKeyAndOrderFront:] #19 0x93827708 in -[NSApplication _cycleWindowsReversed:] #20 0x93789988 in _NSKeyboardUIHandleSymbolicHotKey #21 0x937e49a8 in -[NSApplication _handleKeyEquivalent:] #22 0x936ee408 in -[NSApplication sendEvent:] #23 0x936e5d10 in -[NSApplication run] #24 0x937d687c in NSApplicationMain #25 0x005d9fac in main at main.m:13 The crash log doesn't touch any of my classes, so I thought I'd see if anyone is familiar with this crash. Best Wishes, Rob