Select Previous Version to compare the part edition loaded in your image with the part's previous version in the library.

Selecting Previous Version opens a Changes Browser that displays the contents of the part edition in your image and part's previous version in the library. Using this browser, you can compare the editions' contents. If the version in the library has what you want to work with, select Load Alternatives from the appropriate menu.

For detailed information on comparing parts, refer to the Smalltalk User Guide.