Apple Reverts macOS Window Resizing Fix After Partial Improvement Fails to Satisfy

When Apple introduced rounded corners in macOS Tahoe, developers quickly noticed a usability regression: the window resizing handles didn't follow the new visual design. Instead of aligning with the rounded corners, the active resizing areas remained stubbornly square, creating a disconnect between visual design and functional behavior.

In response to community feedback, Apple initially addressed the issue in macOS 26.3 Release Candidate (RC). Release notes explicitly stated the problem had been resolved. Independent verification came through a custom test application that visually mapped the active resizing regions using color-coded feedback: red for click-responsive areas, green for bidirectional resizing, yellow for single-axis resizing, and blue for dead zones. The results showed Apple had indeed modified the behavior:

Visual mapping confirms resizing areas now follow the rounded corner design in macOS 26.3 RC

The solution came with an unexpected tradeoff. While the resize areas now respected the window's rounded corners, the vertical/horizontal-only resize zone (marked in yellow) shrank from 7 pixels to 6 pixels thick – a 14% reduction in target area. This made the already precise targeting requirement for single-axis resizing even more challenging, particularly on high-density displays.

When macOS 26.3 reached final release, the situation took another turn. Subsequent testing revealed Apple had completely reverted the corner-following behavior. Resizing handles returned to their original square configuration, ignoring the window's curved edges:

Final release reverts to square resizing regions despite rounded visual design

Apple's documentation reflected this reversal. The release notes were updated to demote the issue from "Resolved" back to "Known Issue" status, confirming the temporary fix didn't meet their quality threshold:

Official release notes now classify the resizing behavior as a known issue

This sequence highlights the delicate balance required in UI engineering. While Apple's initial solution technically achieved visual consistency, the practical impact of reduced resize target area likely outweighed the aesthetic improvement. The retraction demonstrates how even resolved issues can reemerge when real-world usability metrics conflict with theoretical solutions. For developers and designers, this serves as a case study in how subtle interaction details – measured in single-pixel increments – can derail seemingly straightforward interface improvements. With the issue officially acknowledged but unresolved, users must again navigate the disconnect between macOS's visual language and its underlying interaction model.