Hi @DTS Engineer Travis, Thanks for the quick reply. As I mentioned in my original message, I haven't been able to recreate this condition in a sample project. I'd love to have a private conversation and show the issue in more detail, but we're ineligible to file a DTS ticket due to it. As you can see from the example above, the setup in the test window is all very simple so there must be something else causing this not to work properly. I understand what you're saying about the layer clipping, however there's no code associated with that window. No subclassed controls, no modified layers, no swizzling that I can see. We shouldn't need to do anything to get the truncation to work. One additional data point I can give you is that, before the issue occurs, we have this: p ((NSPopUpButton *)0x13426484d00).bounds (NSRect) (origin = (x = 0, y = 0), size = (width = 300, height = 24)) p (NSRect)[((NSPopUpButton *)0x13426484d00).cell titleRectForBounds:((NSPopUpButton *)0x13426484d00).bounds] (NSRect) (origin = (x = 5, y = 4), size = (width = 265.5, height = 16)) After changing screen, the bounds are the same but the titleRectForBounds method returns a rect that doesn't make sense to me. (NSRect) (origin = (x = -58.5, y = 4), size = (width = 393.5, height = 16)) Why would it return a rect that is larger than the bounds provided as input? Hope this helps narrow down the issue.

Thanks @DTS Engineer (Kevin) for the deeper investigation. Can we expect that this will be fixed in a future macOS release then? If so, please keep us posted with progress on the issue. Alberto