# How what-if planning works

In what-if mode, a planning change is kept as a proposal instead of being saved. A proposal keeps the values you set, such as a new **Finish**.

Teamhood works out what those values move each time the plan changes, and shows the result over the live plan. None of your proposals reaches your organization until you choose **Apply**.

## What a proposal keeps

- A planning change is a change to **Start**, **Finish**, **Duration (d)**, **Estimate (h)**, **Assignees** or a dependency.
- Planning changes also include hours on a schedule: the hours of an item per person per day, reserved time, and marking reserved time tentative or firm.
- A proposal keeps what you set, not what it moved. The dates it moved are worked out again from the live plan every time.
- Your proposals live in this browser tab only. They are not stored anywhere, so closing or reloading the tab asks first.
- One gesture is one step. `⌘Z` or `Ctrl+Z` steps back one gesture, such as one drag or one paste. `⌘⇧Z` or `Ctrl+Shift+Z` steps forward again.
- Unticking a change in **Review** shows the plan without it. Every ticked change after it is worked out again.

## What you see

- On the Gantt, a moved bar has a dashed amber outline, and a grey dashed outline shows where the bar is now. A moved milestone shows its shift, such as +4d. A proposed dependency is dashed, and a removed one is not drawn.
- On a schedule, the proposed load is the fill. A cell in the load row whose hours the change altered has a dashed amber outline, and hovering it shows the proposed and current hours. The hour cells on an item row show the proposed hours with no outline. A day newly over capacity turns red. A day over capacity in both plans has a soft red wash and red text. A day the change relieves shows no red.
- In a list cell, the current value stays, and an amber chip after it shows the shift, such as +3d. Hovering the cell shows the proposed value. A value with no shift, such as **Assignees**, shows the proposed value in the chip.
- In item details, the current value is struck through, then the proposed value follows. You can edit it again in either place.
- List order, filters, grouping and rollups use the live values. A proposed change can therefore leave a row where it was.

## What the check counts

The bar at the bottom counts your changes, the worst deadline impact and the people newly over capacity. The check covers everything you can see in your organization, not only the view on screen. A schedule view that measures load another way says **This view measures load differently from the what-if check**.

## When a colleague edits the same plan

- Colleagues' edits still arrive. Your proposals sit over the live plan, so their edits update what you see.
- When a colleague changes a value that your change also sets, **Review** shows **Changed by someone else to** and their value. **Apply** waits until you choose **Overwrite** on that line.
- If the colleague changes that value again, the line asks again.
- A colleague who set the same value as yours is not a conflict, because nothing would be overwritten.

## What is unavailable

- Edits that are not planning changes are disabled and say **Not available in what-if mode**. This includes titles, status, comments, time logs, creating or deleting items, and sending in Chat. A few refuse when you use them, and say **Turn off what-if mode to make this change**.
- Time off and working weeks cannot be changed in the mode, because they set capacity. **Time off** in the menu of a schedule sweep is disabled and says **Not available in what-if mode**.
- On a schedule whose estimate is not one of the planning fields above, item hour cells are locked in the mode. Pointing at the item's bar says **Not available in what-if mode**, and clicking it opens the item. Changing those hours also changes that field, which a proposal does not hold.
- On the Gantt, **Export to PDF** and **Critical path** are disabled until the mode is off. A baseline comparison is hidden until then too.
- An **Undo** on a message does nothing in the mode. It says **Turn off what-if mode to make this change**, and the buttons of the **Undo** panel are disabled. Only `⌘Z` or `Ctrl+Z` steps back, through your proposals.

## When you apply

- **Apply** turns the mode off, then saves the ticked changes through the normal edits. All of them are one step in the undo history.
- A change you can no longer apply, such as one your role does not allow or one whose item was deleted, shows why in **Review**. **Apply** waits until you untick it.
- While **Apply** saves, `⌘Z` or `Ctrl+Z` does nothing and says **Wait until your changes are saved**.
- If a change cannot be saved, that change is reverted and a message says so. The other changes stay saved.

## Worked example

Launch is a milestone that waits for Build. You turn on **What-if** and drag Build a week later on the Gantt.

1. Build's bar moves, and a grey dashed outline shows where Build is now.
2. Launch moves too, because it waits for Build, and shows how far it moved.
3. The bar at the bottom says that the Launch milestone moves.
4. You open **Review** and untick the change. Build and Launch show where they are now, and nothing was saved.

## Behaviours that surprise people

- A card dropped on a board in the mode snaps back, because the board shows the live plan. When the drop changes a planning field, such as **Assignees**, **Apply** still saves it. Any other drop is refused.
- A sign-out turns the mode off without asking, and your proposals are lost.

## Next

- [Try a change before you make it](../../views/try-a-change-before-you-make-it/)
- [How dependency scheduling works](../dependency-scheduling/)
- [How capacity and time off work](../capacity-and-time-off/)