MacOS 26 Tahoe complicates window resizing due to a poorly designed hit target area, primarily outside the window due to large corner radii, making resizing harder. The absence of a visible resize indicator, removed since Mac OS X 10.7, led to confusion about window resizability. Apple prioritized aesthetics over usability, resulting in a frustrating experience. The recommendation is to avoid upgrading to Tahoe or downgrade if already upgraded.
https://daringfireball.net/2026/01/resizing_windows_macos_26