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Relationship Editor

Applies to: Pro · Enterprise Last updated: 27-Feb-2026

Overview​

The Assign Relationship Dialog lets you create dependencies between activities. Select a source activity, choose predecessor or successor direction, pick one or more target activities, set the relationship type and lag, then create the dependencies in a single action. The dialog supports batch creation, WBS tree grouping, and validates against circular dependencies.

Prerequisites​

  • Active Pro or Enterprise subscription
  • Editor Mode enabled
  • At least one project with two or more activities

Opening the Relationship Editor​

Open the dialog from:

  • Editor Context Menu → Add Predecessor… or Add Successor…
  • Activity Details Panel → Predecessors or Successors tab → Add button
  • Gantt Chart → Drag to Link creates relationships directly

Dialog Layout​

The dialog anchors to a source activity and opens in either Predecessor or Successor direction.

Relationship Types​

CodeTypeDescription
FSFinish-to-StartSuccessor starts after predecessor finishes (most common)
SSStart-to-StartSuccessor starts when predecessor starts
FFFinish-to-FinishSuccessor finishes when predecessor finishes
SFStart-to-FinishSuccessor finishes when predecessor starts (rare)

The default type is FS (Finish-to-Start).

Lag​

Enter a lag value in hours. The value can be:

  • Positive — adds a delay between the linked activities
  • Zero — no delay (default)
  • Negative — creates a lead (overlap) between activities

Lag is converted to hours internally using the calendar's hours-per-day setting.

Activity Selection​

Search & Filter​

  • Text search — filter by Activity ID or Activity Name (uses deferred value for performance)
  • Status filter — filter by activity status (Not Started, In Progress, Complete)
  • WBS grouping — toggle to group activities in a WBS tree hierarchy for easier navigation

Grid Columns​

ColumnWidthDescription
Activity ID160pxUnique activity identifier
Activity Name280pxDescriptive activity name
Status110pxCurrent activity status
WBS Path200pxFull WBS hierarchy path

All columns are resizable via drag handles.

Multi-Select​

Select multiple target activities to create relationships in batch. Selected rows are highlighted and all receive the same relationship type and lag value.

Validation​

The editor validates relationships before creation:

CheckDescription
Self-referenceCannot create a relationship from an activity to itself
DuplicateCannot create a relationship that already exists
Circular dependencyCannot create a relationship that would form a logic loop

If validation fails, the dialog shows an error message and prevents creation.

Batch Creation​

When multiple activities are selected, clicking OK creates all relationships in a single BatchCommand. This means:

  • All relationships are created atomically
  • A single Undo reverses the entire batch
  • Progress is immediate — no need to create relationships one at a time

Tips & Best Practices​

  • Use FS (Finish-to-Start) for most dependencies — it represents the most natural logic flow
  • Avoid SF (Start-to-Finish) relationships unless you have a specific scheduling need
  • Keep lags to a minimum — excessive lags are flagged by the Lags quality check
  • Use negative lags (leads) sparingly — they are flagged by the Leads quality check
  • Enable WBS grouping when working with large schedules to find activities faster