When using Designer, the Designer Options dialog normally contains a tab for specifying various WL Assignment settings. These options are accessible by selecting Customize > Designer Options via the main ArcFM menus.
A condition has been identified where the WL Assignment tab becomes absent from the Designer Options dialog.
This behavior is triggered when the name of the Work Location feature class does not match WorkLocation.
To resolve the issue, use ArcCatalog and expand the DesignerDataset within your data environment. Located the WL feature class and set the name to WorkLocation.