I saw a couple of instance of this leak after the following steps: 1. launch Safari to an empty page 2. visit bugzilla.opendarwin.org 3. search for all open WebKit bugs I clicked around a few times also, so these steps might not be enough (also, 'leaks' does not give fully repeatable results). This smells like a localized (thus easy to fix) problem to me. Leak: 0x1dc5e610 size=16 0x1dc74a20 0x1dc75520 0x1dc710b0 0x00010001 ..J ..U ........ Call stack: [thread 30df]: | 0x0 | start | _start | main | NSApplicationMain | -[NSApplication run] | - [BrowserApplication nextEventMatchingMask:untilDate:inMode:dequeue:] | -[NSApplication nextEventMatchingMask:untilDate:inMode:dequeue:] | _DPSNextEvent | BlockUntilNextEventMatchingListInMode | ReceiveNextEventCommon | RunCurrentEventLoopInMode | CFRunLoopRunSpecific | __CFRunLoopRun | __CFRunLoopDoObservers | _handleWindowNeedsDisplay | -[BrowserWindow displayIfNeeded] | -[NSWindow displayIfNeeded] | -[NSView displayIfNeeded] | - [NSView _displayRectIgnoringOpacity:isVisibleRect:rectIsVisibleRectForView:] | -[NSThemeFrame _recursiveDisplayRectIfNeededIgnoringOpacity:isVisibleRect:rectIsVisibleRectForView:topView:] | - [NSView _recursiveDisplayRectIfNeededIgnoringOpacity:isVisibleRect:rectIsVisibleRectForView:topView:] | -[NSView _recursiveDisplayRectIfNeededIgnoringOpacity:isVisibleRect:rectIsVisibleRectForView:topView:] | - [NSView _recursiveDisplayRectIfNeededIgnoringOpacity:isVisibleRect:rectIsVisibleRectForView:topView:] | -[NSView _recursiveDisplayRectIfNeededIgnoringOpacity:isVisibleRect:rectIsVisibleRectForView:topView:] | - [NSView _recursiveDisplayRectIfNeededIgnoringOpacity:isVisibleRect:rectIsVisibleRectForView:topView:] | -[NSView _recursiveDisplayRectIfNeededIgnoringOpacity:isVisibleRect:rectIsVisibleRectForView:topView:] | - [NSView _recursiveDisplayAllDirtyWithLockFocus:visRect:] | CFArrayApplyFunction | _recursiveDisplayInRect2 | -[NSView _recursiveDisplayAllDirtyWithLockFocus:visRect:] | CFArrayApplyFunction | _recursiveDisplayInRect2 | -[NSView _recursiveDisplayAllDirtyWithLockFocus:visRect:] | CFArrayApplyFunction | _recursiveDisplayInRect2 | - [WebHTMLView(WebPrivate) _recursiveDisplayAllDirtyWithLockFocus:visRect:] | -[WebHTMLView (WebPrivate) _web_layoutIfNeededRecursive:testDirtyRect:] | -[WebHTMLView(WebPrivate) _layoutIfNeeded] | -[WebHTMLView layout] | -[WebHTMLView layoutToMinimumPageWidth:maximumPageWidth:adjustingViewSize:] | -[WebCoreBridge forceLayoutAdjustingViewSize:] | KWQKHTMLPart::forceLayout() | KHTMLView::layout() | DOM::DocumentImpl::recalcStyle(DOM::NodeImpl::StyleChange) | DOM::ElementImpl::recalcStyle (DOM::NodeImpl::StyleChange) | DOM::ElementImpl::recalcStyle(DOM::NodeImpl::StyleChange) | DOM::ElementImpl::recalcStyle(DOM::NodeImpl::StyleChange) | DOM::ElementImpl::recalcStyle (DOM::NodeImpl::StyleChange) | DOM::ElementImpl::recalcStyle(DOM::NodeImpl::StyleChange) | DOM::ElementImpl::recalcStyle(DOM::NodeImpl::StyleChange) | DOM::ElementImpl::recalcStyle (DOM::NodeImpl::StyleChange) | DOM::ElementImpl::recalcStyle(DOM::NodeImpl::StyleChange) | DOM::ElementImpl::recalcStyle(DOM::NodeImpl::StyleChange) | DOM::ElementImpl::recalcStyle (DOM::NodeImpl::StyleChange) | DOM::ElementImpl::recalcStyle(DOM::NodeImpl::StyleChange) | DOM::ElementImpl::recalcStyle(DOM::NodeImpl::StyleChange) | DOM::HTMLSelectElementImpl::recalcStyle(DOM::NodeImpl::StyleChange) | DOM::HTMLGenericFormElementImpl::recalcStyle(DOM::NodeImpl::StyleChange) | khtml::RenderSelect::updateFromElement() | DOM::HTMLSelectElementImpl::recalcListItems() | QMemArray<DOM::HTMLGenericFormElementImpl*>::resize(unsigned) | KWQArrayImpl::resize (unsigned long) | khtml::main_thread_realloc(void*, unsigned long) | realloc