About comparing with a change set predecessor in a UCM environment
A change set lists all versions you have created while working on a specific activity. In some cases, you create more than one version of an element for a specific activity. For example, for the activity Change copyright strings, you check in a version of prog.c and realize later that you missed a string in the file. You then set your view to the activity Change copyright strings, check out prog.c, modify the string, and check in the file.
To see the changes you have made to an element while working on an activity, you can compare a version in the activity change set with the version that immediately precedes the change set. For example, the change set predecessor of prog.c is version 2.
You can compare any version of prog.c in the change set with version 2.