Flutter web takes time to open dialog

[thealmamun]

It seems there's a junk creates when i click on dropdown & takes 3-5 seconds to open the icons dialog.

flutter doctor :

Doctor summary (to see all details, run flutter doctor -v):
[✓] Flutter (Channel beta, 2.2.0-10.1.pre, on Mac OS X 10.15.1 19B88 darwin-x64, locale en-GB)
[✓] Android toolchain - develop for Android devices (Android SDK version 30.0.2)
[!] Xcode - develop for iOS and macOS
✗ Xcode installation is incomplete; a full installation is necessary for iOS development.
Download at: https://developer.apple.com/xcode/download/
Or install Xcode via the App Store.
Once installed, run:
sudo xcode-select --switch /Applications/Xcode.app/Contents/Developer
sudo xcodebuild -runFirstLaunch
! CocoaPods 1.9.1 out of date (1.10.0 is recommended).
CocoaPods is used to retrieve the iOS and macOS platform side's plugin code that responds to your plugin usage on the Dart side.
Without CocoaPods, plugins will not work on iOS or macOS.
For more info, see https://flutter.dev/platform-plugins
To upgrade see https://guides.cocoapods.org/using/getting-started.html#installation for instructions.
[✓] Chrome - develop for the web
[✓] Android Studio (version 4.1)
[!] Android Studio
✗ Android Studio not found at /path/to/android/studio/Contents
[✓] VS Code (version 1.55.2)
[✓] Connected device (1 available)