Summary

Gruber dissects a fundamental usability regression in macOS 26 Tahoe where the large corner radius on windows causes 75% of the invisible resize hit target to fall outside the window bounds. He traces the history back to Mac OS X 10.7 Lion, when Apple removed the visible resize grippy-strip affordance and made scroll bars invisible by default — decisions he considers mistakes but at least logically defensible. The new Tahoe corner radiuses break the implicit contract that remained: users could still intuit a resize target inside the window corner. Gruber argues this exemplifies design driven by appearance rather than function, violating Steve Jobs's principle that design is how things work. He concludes by recommending users not upgrade to macOS 26 Tahoe, or downgrade if they already have.

Key Insight

macOS Tahoe's oversized corner radiuses broke a fundamental spatial contract — that you resize a window by grabbing inside it — proving the redesign prioritized looks over how things actually work.

Spicy Quotes (click to share)

• 4

  It turns out that my initial click in the window corner instinctively happens in an area where the window doesn't respond to it.

• 6

  I think it was a grave error to make scroll bars invisible by default.

• 5

  The visible resize affordance didn't just tell you where to click to resize the window, it also told you that the window could be resized in the first place.

• 6

  It would make no sense whatsoever for the click target to resize a window to be outside the window. Why would anyone expect that?

• 7

  You pick up a thing to move it or stretch it by grabbing the thing. Not by grabbing next to the thing.

• 9

  The windows on MacOS 26 Tahoe don't really have comically large, childish corner radiuses. They just look like they do because some jackasses at Apple thought they looked better that way.

• 7

  It's a straight-up inversion of Steve Jobs's maxim that design is about how things work, not how they look.

• 8

  I can think of no better example to prove that the new UI in MacOS 26 Tahoe was designed by people who do not understand or care about the most basic fundamental principles of good design.

Tone

excoriating