There are several points when 4D saves all of the changes you've made in the design environment:

When you choose Use------>User (Option + U) (Ctrl + U) to go to the User environment.

When you click the User window to go to the User environment.

When you click the close box for the object method's listing editor window. (saves only the current window)

When you choose File-----> Save (Option + S) (Ctrl + S). (saves only the current window)

When you choose File------> Close (Option + W) (Ctrl + W). (Closes only the current window).

Thus, there is seldom a need to choose File-----> Save (Option + S) (Ctrl + S). 4D saves any changes you have made when you switch to the User environment or close the window.