MouseMoved notification in NSTextView produces message "Shared items array is empty"

Question

I am using a custom mouseMove event in NSTextView to set the cursor to a pointer when it's outside the content insets. When it's inside the editable area, I'm calling [super mouseMove]:

- (void)mouseMoved:(NSEvent*)event {
    NSPoint point = [self convertPoint:event.locationInWindow fromView:nil];
    
    if ((point.x > self.textContainerInset.width &&
         point.x < self.frame.size.width - self.textContainerInset.width)
    ) {
        [super mouseMoved:event];
    } else if (point.x > 10) {
        [NSCursor.arrowCursor set];
    }
}

When selecting a line break in my text (meaning the empty part at the end of a line) and hovering mouse over the selection, [super mouseMoved:event] produces the following message on every pixel the mouse moves:

Appname[29357:853497] [Framework] Shared items array is empty
Appname[29357:853497] [Framework] No shared items can be accessed

I am confused why this happens and what might be the cause?

EDIT: This seems to happen even without subclassing NSTextView. It might be a bug in macOS Catalina. For me, it doesn't seem to cause any other problems.

Casia

Does the example project HoverTest produce the messages? – Anatole

Yes. It sometimes requires some cmd-tabbing, but it produces the exact messages, at least for me on 10.15.4. – Casia

In MainMenu.xib the class of the text view isn't TextView and the textView outlet of AppDelegate isn't connected. Is your code executed? – Anatole

Uh, I managed to save a copy into Dropbox and not the intended version. However, the same effect seems to happen even without the custom TextView class or the code, so I'm guessing it's a NSTextView bug in the latest macOS. – Casia

I have this exact problem and this question is the only thing I found with the "No shared items can be accessed" search term. Have you managed to find the issue? – Odonnell

Unfortunately not. I'm guessing it's a system bug/feature, and doesn't seem to cause any other problems besides flooding the log full of alerts. – Casia

I am facing this same bug too on MacOS 10.15.4 Catalina. And this seems to be causing my app to unable to read the UserDefaults. – Villatoro

Answer 1

I found a solution. It conflicts with the standard recommendation for subclassing. But as far as I can tell, it introduces no unwanted behavior. Subclass your NSTextView and override this method (yes, without calling the superclass, which is the part that makes the solution work, sigh):

override func mouseMoved(with event: NSEvent) {} // swift

Meliamelic

Answer 2

In my case, I have to call addTrackingArea method to enable mouse tracking, and the console stopped wanring No shared items can be accessed as well.

eg:

class TrackableImageView: NSImageView {

override func mouseEntered(with event: NSEvent) {
    super.mouseEntered(with: event)
}

override func mouseExited(with event: NSEvent) {
    super.mouseExited(with: event)
}

override func viewDidMoveToWindow() {
    super.viewDidMoveToWindow()
    addTrackingArea(.init(rect: frame, options: [.mouseEnteredAndExited, .activeInKeyWindow], owner: self))
     
}

}

Galloping