# Dynamic Subtasks Filter

The Dynamic Subtasks Filter opens an instant, focused window onto one task's subtree. Run it on any task that has subtasks and Operon builds a live project tree of just that task's children, locked to the task itself. It is the fastest way to drop into a branch of work without building a filter or leaving the surface you are on.

> **MEDIA-DOCS-059-1:** The Dynamic Subtasks Filter open over a note, showing one task's subtask tree.

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## How to open it

Run the **Subtasks** action from a task's [contextual menu](/docs/docs-042-contextual-menu-actions/). Because that menu is available wherever a task appears, you can open the filter from a filter row, a Calendar item, a Kanban card, a pinned task, or an inline task in a note.

> **MEDIA-DOCS-059-2:** The Subtasks action in a task's contextual menu, which opens the filter.

![MEDIA-DOCS-059-2 - The Subtasks action in a task's contextual menu, which opens the filter](/assets/docs/media/MEDIA-DOCS-059-2.png?v=cf4ab8b29fea)

The action appears only when it can do something useful: the task must be open and must actually have subtasks. A leaf task with no children does not show it.

## What it shows

The filter is locked to the task you opened it on. Its one condition is dynamic and cannot be edited: it matches the children of that task's `operonId`. The result is a self-contained project tree for that branch, and it stays live, so completing or adding a subtask updates the window in place.

## How it compares to the Dynamic File Task Filter

The two are siblings: both are operonId-locked subtask filters that Operon builds for you. They differ in surface and trigger.

| | Dynamic Subtasks Filter | [Dynamic File Task Filter](/docs/docs-026-dynamic-file-task-filter/) |
|---|---|---|
| Where it appears | A pop-up window | Embedded in a file task's note body |
| How it opens | On demand, from the Subtasks action | Automatically, in Reading View and Live Preview |
| Works on | Any open task with subtasks, inline or file | File tasks only |
| Settings | Auto-expand, show only open | Enabled, placement, auto-expand, show only open |

Use the Dynamic Subtasks Filter for a quick look at any branch from anywhere. Use the Dynamic File Task Filter when a file task should always carry its subtask tree inside its own note.

## Settings

The filter has its own controls in **Settings → Operon → Views → Filters → Dynamic Subtasks Filter**:

- **Auto-expand subtasks**: automatically expand the subtask tree when it is at or below the size you choose, so small branches open fully and large ones stay tidy.
- **Show only open subtasks**: keep finished children out of the window so you see only what is left to do.

## Related

- [Operon Docs MOC](/docs/docs-001-operon-docs-moc/)
- [Parent and sub-tasks](/docs/docs-016-parent-and-sub-tasks/)
- [Filter View](/docs/docs-025-filter-view/)