Reference lookup On forms, the reference lookup icon ( in UI16/UI15) appears by editable reference fields. Clicking the reference lookup icon displays a list of records on the referenced table. When List v3 is enabled, the list appears in a popover. Otherwise, the list appears in a pop-up window. Figure 1. Reference lookup list popover Figure 2. UI15 reference lookup list pop-up Figure 3. UI11 reference lookup list pop-up Tree picker lookupThe reference lookup can be rendered in the tree picker format by modifying the dictionary and adding the attribute tree_picker.