One of the new features of the 8.5 Macintosh OS is the Application Switcher Extension,which gives the Macintosh OS the ability to switch between applications. Application Switcher uses the Command - Tab keys to switch between applications. By coincidence, is the same default key combination that 4D uses to add a record in a subform.
There are two work-arounds for this conflict. One way is to modify the keyboard shortcut in 4D uses with Customizer Plus. The steps to do this are:
1) Open your database, or application with 4D Customizer Plus.
2) Open the "Keys" resource.
3) Change the keyboard shortcut for "Add to Included"
4) Save your changes.
The other possible work-around is to change the keyboard shortcut for Application Switcher. The steps to do this are:
1) Go to the Finder and select "Help Center" in the Help menu.
2) Enter "Switcher" in the search field and click on the Search button.
3) Click on the "Switching between open programs" link.
4) Scroll down to "Help me modify the keyboard short cuts" link and click on it.
5) Help Center will provide a number of dialogs that will lead you through changing the keyboard shortcut.