react / react/react-native

Modal UI breaks when using align related CSS properties

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#52,927 5 comments 0 reactions 0 assignees View on GitHub

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Component: Modal Needs: Triage :mag:
Dominant language
C++
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Description

Description

When the child view of a modal is given alignItems: 'center' or justifyContent: 'center' the UI breaks while the modal is opens.

I could reproduce this behaviour when the modal contains an Image or an SVG, but I've also seen text flickers in the same manner.

While the flicker is prominent in New Architecture, it is also occurring in legacy when trying multiple times.

Steps to reproduce
  1. Make a modal with child view having alignItems: 'center'
  2. Add an Image and a Text to the child View
  3. Flicker occurs when the modal is opened.
React Native Version

0.80.2

Affected Platforms

Runtime - Android

Output of npx @react-native-community/cli info
System:
  OS: macOS 15.5
  CPU: (8) arm64 Apple M1
  Memory: 178.75 MB / 8.00 GB
  Shell:
    version: "5.9"
    path: /bin/zsh
Binaries:
  Node:
    version: 20.18.1
    path: ~/.nvm/versions/node/v20.18.1/bin/node
  Yarn:
    version: 3.6.4
    path: /opt/homebrew/bin/yarn
  npm:
    version: 10.8.2
    path: ~/.nvm/versions/node/v20.18.1/bin/npm
  Watchman:
    version: 2025.03.10.00
    path: /opt/homebrew/bin/watchman
Managers:
  CocoaPods:
    version: 1.16.2
    path: /opt/homebrew/bin/pod
SDKs:
  iOS SDK:
    Platforms:
      - DriverKit 24.5
      - iOS 18.5
      - macOS 15.5
      - tvOS 18.5
      - visionOS 2.5
      - watchOS 11.5
  Android SDK:
    API Levels:
      - "28"
      - "29"
      - "31"
      - "32"
      - "33"
      - "34"
      - "35"
    Build Tools:
      - 28.0.3
      - 30.0.3
      - 33.0.1
      - 34.0.0
      - 35.0.0
    System Images:
      - android-34 | Google APIs ARM 64 v8a
      - android-UpsideDownCakePrivacySandbox | Google Play ARM 64 v8a
    Android NDK: Not Found
IDEs:
  Android Studio: 2024.2 AI-242.23339.11.2421.12550806
  Xcode:
    version: 16.4/16F6
    path: /usr/bin/xcodebuild
Languages:
  Java:
    version: 17.0.1
    path: /usr/bin/javac
  Ruby:
    version: 2.6.10
    path: /usr/bin/ruby
npmPackages:
  "@react-native-community/cli":
    installed: 19.1.1
    wanted: 19.1.1
  react:
    installed: 19.1.0
    wanted: 19.1.0
  react-native:
    installed: 0.80.2
    wanted: 0.80.2
  react-native-macos: Not Found
npmGlobalPackages:
  "*react-native*": Not Found
Android:
  hermesEnabled: true
  newArchEnabled: true
iOS:
  hermesEnabled: true
  newArchEnabled: true
Stacktrace or Logs
Not applicable, since it is a UI bug and nothing is logged as crash
MANDATORY Reproducer

https://github.com/sanyam12/ModalFlicker

Screenshots and Videos

https://github.com/user-attachments/assets/5f8008c6-9982-47c2-bbcd-1ed5566dddfa

Current Behaviour: Modal content is first displayed in top right corner, then at it's intended position.
Expected Behaviour: Modal content should be displayed in the center without any flicker.

Contributor guide

Open the contributing guide

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start by running the mandatory reproducer at github.com/sanyam12/ModalFlicker on Android with React Native 0.80.2, then compare the modal behavior with alignItems or justifyContent set to center. Verify the result in both New Architecture and legacy mode; done means modal content appears centered immediately without flicker, including when it contains an Image, SVG, or Text.

Written by the indexing model from the issue text.

Assessment

Tech stack
android, react-native
Domain
mobile
Issue type
Bug
Difficulty
4/5
Estimated time
3-5 days
Activity status
Quiet
Clarity
Mostly clear
Newbie friendliness
45/100

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