Predecessors will be shown with a line connecting them to the current item.
Select the 
icon to add a predecessor.
Item Identifier: Select the field which identifies the item the predecessor is being defined for.
Predecessor Identifier: Select the field which identifies the predecessor.
Colour: Select a keyword field, the colours associated with the keywords will be used for the links between items and override the default colour.
Default Colour: Select a default colour for the links between items. This colour will be used unless a keyword field has been assigned to the colour.