The rectangle (in screen coordinates) of the item’s visible content.
- macOS 10.10+
The rectangle in this property corresponds to the onscreen frame rectangle of the item. This rectangle may or may not intersect the
source rectangle of the item. An intersection of the rectangles means that at least part of the item is visible onscreen.
The rectangle in this property may be a clipped version of the source frame or it might be
NSZero if the item is offscreen or the clipping rectangle cannot be determined. The system treats a value of
NSZero as meaning the item is fully visible.