When disabling the opacity slider of color panels, my app crashes with unsatisfiable layout constraints. Feel free reproduce with a minimal test project: A macOS app based on the Xcode 26.0 template with only one line added to the ViewController's viewDidLoad() function:
NSColorPanel.shared.showsAlpha = false
The issue doesn't occur if this property is set to "true" or not set at all.
I just filed a corresponding bug report (FB20269686), although I don't expect any feedback from Apple ... as numerous issues I reported were never updated or commented at all (after migrating from RADARs).
Topic:
UI Frameworks
SubTopic:
AppKit