Thank you for your answer. It then seems to me something is lacking, it would be nice if the ControlWidgetToggle would be informed when the parent app is terminated. I have submitted a suggestion using the feedback assistant.

The .m file can be placed in the folder 'DecimalRoundFix. Add "DecimalRoundFix" to the dependencies of your main target. You can then use @import DecimalRoundFix to import the fix in your swift code. When finished, write a XCTest to test your code to make sure that everything works as it should.

If I am correct you cannot mix Swift and Objective-C in one target. In one package, or all (depending on how your packages depend on each other) add an additional target where you place the Objective C files of the fix (or if you have already an objective-C target, you could add them there). Target definition should be something like: .target(name: "DecimalRoundFix", dependencies: []). Make sure that the header file is placed in the special folder named 'DecimalRoundFix/include'.

Yes works in production.

Thanks a lot for this comment. I was struggling for a day with this issue until I saw your solution. After I removed a NSToolbarItem(itemIdentifier: itemIdentifier, barButtonItem: barButtonItem) from the toolbar, all my windows and tabs responded to key commands as expected.