---
title: "Overlay Migration Guide"
description: "This document tracks the Dify-web migration away from legacy overlay APIs."
type: skill
canonical_url: https://claudary.paisolsolutions.com/skills/overlay-migration
source: "Claudary"
difficulty: intermediate
author: "Claude Code Knowledge Pack"
date: 2026-07-10T11:31:39.059Z
license: CC-BY-4.0
attribution: "Overlay Migration Guide — Claudary (https://claudary.paisolsolutions.com/skills/overlay-migration)"
---

# Overlay Migration Guide
This document tracks the Dify-web migration away from legacy overlay APIs.

## Overview

# Overlay Migration Guide

This document tracks the Dify-web migration away from legacy overlay APIs.

> **See also:** [`packages/dify-ui/README.md`] for the permanent overlay / portal / z-index contract of the replacement primitives. This document covers the one-off migration mechanics (allowlist, deprecated import paths, coexistence z-index strategy) and is expected to shrink and eventually be removed once the legacy overlays are gone.

## Scope

- Deprecated imports:
  - `@/app/components/base/portal-to-follow-elem`
  - `@/app/components/base/tooltip`
  - `@/app/components/base/modal`
  - `@/app/components/base/select` (including `custom` / `pure`)
  - `@/app/components/base/dialog`
- Replacement primitives:
  - `@langgenius/dify-ui/tooltip`
  - `@langgenius/dify-ui/dropdown-menu`
  - `@langgenius/dify-ui/context-menu`
  - `@langgenius/dify-ui/popover`
  - `@langgenius/dify-ui/dialog`
  - `@langgenius/dify-ui/alert-dialog`
  - `@langgenius/dify-ui/select`
  - `@langgenius/dify-ui/toast`
- Tracking issue: <https://github.com/langgenius/dify/issues/32767>

## ESLint policy

- `no-restricted-imports` blocks all deprecated imports listed above.
- The rule is enabled for normal source files (`.ts` / `.tsx`) and test files are excluded.
- Legacy `app/components/base/*` callers are temporarily allowlisted in `OVERLAY_MIGRATION_LEGACY_BASE_FILES` (`web/eslint.constants.mjs`).
- New files must not be added to the allowlist without migration owner approval.

## Migration phases

1. Business/UI features outside `app/components/base/**`
   - Migrate old calls to semantic primitives from `@langgenius/dify-ui/*`.
   - Keep deprecated imports out of newly touched files.
1. Legacy base components in allowlist
   - Migrate allowlisted base callers gradually.
   - Remove migrated files from `OVERLAY_MIGRATION_LEGACY_BASE_FILES` immediately.
1. Cleanup
   - Remove remaining allowlist entries.
   - Remove legacy overlay implementations when import count reaches zero.

## Allowlist maintenance

- If a migrated file was in the allowlist, remove it from `web/eslint.constants.mjs` in the same PR.
- Never increase allowlist scope to bypass new code.

## z-index strategy

All new overlay primitives in `@langgenius/dify-ui/*` share a single z-index value:
**`z-1002`**, except Toast which stays one layer above at **`z-1003`**.

### Why z-[1002]?

During the migration period, legacy and new overlays coexist. Legacy overlays
portal to `document.body` with explicit z-index values:

| Layer                             | z-index        | Components                                               |
| --------------------------------- | -------------- | -------------------------------------------------------- |
| Legacy Drawer                     | `z-30`         | `base/drawer`                                            |
| Legacy Modal                      | `z-60`         | `base/modal` (default)                                   |
| Legacy PortalToFollowElem callers | up to `z-1001` | various business components                              |
| **New UI primitives**             | **`z-1002`**   | `@langgenius/dify-ui/*` (Popover, Dialog, Tooltip, etc.) |
| Toast                             | `z-1003`       | `@langgenius/dify-ui/toast`                              |

`z-1002` sits above all common legacy overlays, so new primitives always
render on top without needing per-call-site z-index hacks. Among themselves,
new primitives share the same z-index and rely on **DOM order** for stacking
(later portal = on top).

Toast stays one layer above the overlay primitives so notifications remain
visible above dialogs, popovers, and other portalled surfaces without falling
back to `z-9999`.

### Rules

- **Do NOT add z-index overrides** (e.g. `className="z-1003"`) on new
  `@langgenius/dify-ui/*` components. If you find yourself needing one, the
  parent legacy overlay should be migrated instead.
- When migrating a legacy overlay that has a high z-index, remove the z-index
  entirely — the new primitive's default `z-1002` handles it.
- `portalToFollowElemContentClassName` with z-index values (e.g. `z-1000`)
  should be deleted when the surrounding legacy container is migrated.

### Post-migration cleanup

Once all legacy overlays are removed:

1. Reduce `z-1002` back to `z-50` across all `@langgenius/dify-ui/*` primitives.
1. Reduce Toast from `z-1003` to `z-51`.
1. Remove this section from the migration guide.

[`packages/dify-ui/README.md`]: ../../packages/dify-ui/README.md

---

Source: [Claudary](https://claudary.paisolsolutions.com/skills/overlay-migration) · https://claudary.paisolsolutions.com