Open new windows as tab not working?

[ron barber]

I had a standalone built using Mac 10.14; LC 9.03.  Sonoma broke the menus (actually the app would not even open) so I upgraded LC to 9.6.10 and that solved the menu problem.

However now a user is reporting and I have confirmed that the option to open new windows as a tab in the existing window no longer works. That is, LC 9.0.3 build respected the tab setting but the 9.6.10 build does not. This is handled by the system preferences in Dock:  “Prefer tabs when opening documents” .

Is this a bug or is there a workaround or do I need to upgrade LC?

Thanks for your suggestions
Ron