# The timeline: blocks, links and milestones

This guide builds on the vocabulary laid out in *[Understanding the timeline in five minutes](/docs/en/demarrer/timeline-en-cinq-minutes/)* and details the gestures: drawing, moving, linking two blocks, placing a milestone, locking.

## Drawing a block

On a named row, click in the time grid where the block should start and **drag** horizontally to the end date, then release. A blue block appears with a text field ready to receive its name; type it and confirm with **Enter**. A start date that falls outside a working slot (a weekend, a closure) is snapped to the next one.

If the text field doesn't open, or you want to rename a block later, **right-click the block › Edit the label** does the same thing at any time.

## Moving, resizing, recoloring

- **Dragging a block** horizontally moves it along the same row. Dragging it onto another row moves it there.
- **Dragging an edge** (left or right) of the block changes its duration.
- **Double-clicking** a block reopens its label for editing, in place.
- **Right-clicking a block** opens a menu: **Edit the label**, **Edit the comment** (or **Comment**, if none exists yet), **Color ▸**, **Add a dependency**, **Place a marker here**, **Actions…** (shortcut **A**), **Lock**, **Delete the block** (shortcut **Del**).
- **Lock** freezes the block's place and existence: it no longer moves, resizes, or gets deleted until unlocked — its label, color, progress, comments and actions stay editable.

## Milestones (icons)

A milestone is an icon placed on a precise date rather than a duration — a site handover, a meeting, an alert. It's placed and handled like a block (right-clicking an empty cell in the time grid offers to insert one), moves, gets renamed and locked the same way.

## Linking two blocks (or icons)

From a block's right-click menu, **Add a dependency** then aim at the second element. A link states that the target can't start before the origin is finished (the most common direction; others are possible — finish-to-finish, start-to-start…).

Two kinds of link, visible on screen:

- **Hard** (solid line): if the origin moves and the constraint is no longer met, the target is **pushed** by the minimum needed — this is what makes a whole project shift cleanly when a single task runs late. It counts toward the critical path.
- **Soft** (dotted line): never moves anything, is never "violated"; useful for showing a logical order without suffering the push — and it's the only link type that can close a loop.

## What happens when you get it wrong

- **A block placed or sized wrong**: drag it again, or **Ctrl+Z** (the **Undo** button, at the top of the ribbon) undoes the last gesture — the button renames itself after the action it's about to undo ("Undo: Place a block"), which helps you check before clicking.
- **A dependency that no longer makes sense**: right-click the link (or from the block) to delete it; the blocks stay where they are, nothing moves back.
- **A locked block you're trying to move**: the gesture is refused (the element doesn't move) — you first have to unlock it from its menu.

## What this page doesn't cover

- **The columns of the left panel, indenting rows**: see *[The grid and columns](/docs/en/guides/grille-et-colonnes/)*.
- **Closures and absences that extend a block**: see *[The calendar, closures and absences](/docs/en/guides/calendrier-fermetures-absences/)*.
- **Named colors in the legend, and the filter that hides rows**: see *[The legend and the filter](/docs/en/guides/legende-et-filtre/)*.
- **Actions to check off on a block, and the progress that comes from them**: see *[A block's actions and its derived progress](/docs/en/guides/actions-et-avancement/)*.