TL;DR
After upgrading to macOS 26 (Tahoe), users report frequent failures when attempting to resize windows. Developers found the visual corner radii no longer match the window's active resize region, causing many clicks at the corner to land outside the functional area.
What happened
Several users and developers noticed that after moving to macOS 26 (Tahoe) attempts to resize windows often fail when grabbing a corner. Developer Norbert Heger analyzed the issue and found the window’s resize hit area is defined as a 19 × 19-pixel zone near each corner. In a window with square corners, roughly 62% of that zone lies inside the visible window; with the much larger corner radii used in Tahoe, about 75% of the 19 × 19 area now falls outside the visible rounded corner. Practically, this means an instinctive click near the rounded corner often misses the active area and the resize action does not start. Commentators including John Gruber have highlighted the mismatch between the visible rounded corners and the underlying square logical geometry, noting it also creates inconsistencies for elements like scrollbars that assume rectangular bounds.
Why it matters
- Common window-management action (corner resizing) can fail frequently, degrading basic usability.
- A mismatch between visual design and hit-testing undermines interface predictability for users.
- Long-time Mac users may be surprised because resizing behaved reliably on prior macOS releases.
- Visual/logical inconsistencies can cascade to other UI elements (for example, scrollbar placement).
Key facts
- Issue observed after upgrading to macOS 26 (Tahoe).
- Developer Norbert Heger examined the problem and published measurements.
- The window’s active resize zone is a 19 × 19-pixel area positioned near the corner.
- Without rounded corners, about 62% of that area would lie inside the window.
- With Tahoe’s large corner radius, roughly 75% of the 19 × 19 area lies outside the visible corner.
- Visual indicators and logical hit regions do not match, so clicking the rounded corner often fails to trigger resizing.
- Commentary from John Gruber called out the visual mess caused by the discrepancy, including scrollbar alignment issues.
- Historically, older macOS versions showed explicit resize handles; those are no longer present.
What to watch next
- Whether Apple issues an official statement or bugfix addressing the corner hit-area mismatch — not confirmed in the source.
- Future macOS updates or betas that adjust corner radii or the reported 19 × 19 resize hit region — not confirmed in the source.
- Community-shared workarounds or developer patches to change hit-testing behavior — not confirmed in the source.
Quick glossary
- Corner radius: The measurement that determines how rounded the corners of a window or box appear; larger values create more curved corners.
- Hit area (hit-testing): The region of the screen where input events (mouse clicks or taps) are recognized and act on a particular UI element.
- Resize handle: A visual or functional affordance that indicates where a user can click and drag to change a window’s size.
- Pixel: The smallest addressable element of a digital display, used here to measure dimensions of interactive regions.
Reader FAQ
Why do my clicks at the rounded corner fail to resize a window?
In macOS 26 the visible corner is rounded but the system’s active resize zone is a 19 × 19-pixel square placed near the corner; much of that square now lies outside the rounded shape, so clicks often miss the active area.
Is this considered a bug or a design choice?
The reporting frames it as a design error by Apple caused by the mismatch between visual corners and logical hit regions.
Will Apple fix this in an update?
Not confirmed in the source.
Did earlier macOS versions have a visible resize indicator?
Yes — older versions used to show a grab handle in the bottom-right corner, which highlighted resizability; that indicator is no longer present.
Apple confirms Google’s Gemini will power new Siri features Chance Miller Jan 12 2026 macOS 26 windows are hard to resize because they aren’t really rounded Ben Lovejoy | Jan 13…
Sources
- macOS 26 windows are hard to resize because they aren’t really rounded
- Option to disable or reduce the Tahoe 26 exaggeratedly rounded corners
- Safari window corners look so strange
- Why It's Difficult to Resize Windows on MacOS 26 Dyehoe
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