Backward-pull cascade

By default, the Timeline cascade is **forward-only** — moving a task pushes its dependents forward when needed, but never pulls anything earlier. v3 adds an opt-in **Backward-pull** mode.

**Turning it on**
On the Timeline tab, find the "Backward-pull" checkbox in the controls bar.

**What changes**
With Backward-pull on, dragging a task to an earlier date will pull its dependents earlier too — but only by their available slack. CPM is respected: nothing slips past its earliest possible start.

**Why it's opt-in**
Backward-pull can quietly compress slack you'd authored intentionally — "I want this task to start two weeks before the deadline so I have buffer". When that's the case, leave the toggle off.

**When to use it**
• You're tightening up a plan after slipping dates earlier in the chain
• You want successors to follow predecessors as early as possible (default project culture for some teams)

The toggle is per-session. Refreshing the page resets it back to forward-only — keeping the safe default in front.