With the introduction of macOS 26 (Tahoe) Apple has changed parts of the GUI design. Most prominently the introduction of "liquid glass", but real disturbing, at least for me, have been the new radius values for window corner roundings. Much larger than in the previous version (macOS 15, Sequoia) and partly even different between applications.
This and some other design features (or flaws) have been addressed with macOS 27 (Golden Gate). However the corner roundings are still larger than back at Sequoia. Fortunately macOS allows to set a global default value for the radius (via the terminal application):
defaults write -g NSConvolutionOverride1 -float 10
Changes take effect after restarting running applications.
| Default radius settings | Value |
|---|---|
| Sequoia | 10 |
| Tahoe | 26 |
| Golden Gate | 16 |
| no roundings | 1 |
Some applications may hardcode the corner radius values. In this case changing the settings doesn't help.
To reset the radius to the system default value run the command:
defaults delete -g NSConvolutionOverride1
Also the floating sidebar can get activated and deactivated this way (default is true for Tahoe and false for Golden Gate):
defaults write -g NSSplitViewItemSidebarDefaultsToFloatingAppearance -bool true
In case the floating sidebar is activated the according sidebar corner radius can be set by (i.e. to 9):
defaults write -g NSSplitViewItemGlassMinimumCornerRadius -float 9
These settings are not officially published by Apple. One have to search for them and hope it works.