Marketing plans enable users to outline and plan for future marketing efforts. When setting up the planned efforts, users may choose to select a source code layout and define the values for each source code part. However, after the planned effort is saved and users attempt to edit it, the source code parts are not visible or available to be changed.
Download and install the latest patch, which contains all fixes from previous patches. If you are running an older version, download and install the latest version and then the patch.