QCocoaView recreates/readds tracking areas for no reason, which causes significant GUI performance issues

- (void)updateTrackingAreas
{
    if (!qwidget)
        return;

    // [NSView addTrackingArea] is slow, so bail out early if we can:
    if (NSIsEmptyRect([self visibleRect]))
        return;

    QMacCocoaAutoReleasePool pool;

    if ([[self trackingAreas] count] > 0)
        return;
	
    // Ideally, we shouldn't have NSTrackingMouseMoved events included below, it should
    // only be turned on if mouseTracking, hover is on or a tool tip is set.
    // Unfortunately, Qt will send "tooltip" events on mouse moves, so we need to
    // turn it on in ALL case. That means EVERY QCocoaView gets to pay the cost of
    // mouse moves delivered to it (Apple recommends keeping it OFF because there
    // is a performance hit). So it goes.
    NSUInteger trackingOptions = NSTrackingMouseEnteredAndExited | NSTrackingActiveInActiveApp
                                 | NSTrackingInVisibleRect | NSTrackingMouseMoved;
    NSTrackingArea *ta = [[NSTrackingArea alloc] initWithRect:NSMakeRect(0, 0, 1, 1)
                                                       options:trackingOptions
                                                        owner:self
                                                     userInfo:nil];
    [self addTrackingArea:ta];
    [ta release];
}