A recent observation by Norbert Heger highlights difficulties in resizing windows in macOS Tahoe. Users have reported failed attempts to resize windows due to the position of the click target. The operating system expects a click within a 19x19 pixel area near the window corner. However, due to the large corner radius implemented in macOS Tahoe, approximately 75% of this designated target area now lies outside the visible window boundary.
Historically, macOS versions prior to 10.7 Lion included a visible resize affordance in the lower-right corner, which served to indicate both the window's resizability and the correct click target. This visual indicator was removed in Mac OS X 10.7 Lion, released in July 2011. The absence of this explicit visual cue required users to infer a window's resizability by moving the mouse cursor to the corner.
Apple's rationale for this change in 2011 likely involved the premise that users were already accustomed to resizing windows from any corner or edge. The change also coincided with the default implementation of invisible scrollbars, which removed the previously available empty space in the corner where the resize affordance had been situated. At that time, macOS did include a small affordance where clicks slightly outside the window's edge would still register as an intended resize.
In macOS Tahoe, the core issue identified is that the majority of the hit target for initiating a window resize is positioned outside the actual window. This design decision has been noted as counter-intuitive to user expectations, as it requires interaction with an area adjacent to the object rather than directly on it.