SDK Setup freezes Downloading Components when SDK is already downloaded

On OSX (10.13.2) I installed Android Studio and flutter and IntelliJ with the Dart and Flutter plugins. When I go in IntelliJ to Tools->Android->SDK Manager and edit the SDK path it filled in the location and everything seems to go fine until I get to a screen that says "Android SDK is up to date."

Good, except I can't click any buttons - Cancel is the only enabled one but clicking it, or trying to close the window does nothing. I have to force close IntelliJ.

## Flutter Doctor

[✓] Flutter (on Mac OS X 10.13.2 17C88, locale en-GB, channel alpha)
• Flutter at /Users/shot/Tim/flutter
• Framework revision 8f65fec5f5 (7 weeks ago), 2017-12-12 09:50:14 -0800
• Engine revision edaecdc8b8
• Tools Dart version 1.25.0-dev.11.0
• Engine Dart version 2.0.0-edge.d8ae797298c3a6cf8dc9f4558707bd2672224d3e

[✓] Android toolchain - develop for Android devices (Android SDK 27.0.3)
• Android SDK at /Users/shot/Library/Android/sdk
• Android NDK location not configured (optional; useful for native profiling support)
• Platform android-27, build-tools 27.0.3
• Java binary at: /Applications/Android Studio.app/Contents/jre/jdk/Contents/Home/bin/java
• Java version OpenJDK Runtime Environment (build 1.8.0_152-release-915-b08)

[-] iOS toolchain - develop for iOS devices
✗ 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
✗ libimobiledevice and ideviceinstaller are not installed. To install, run:
brew install --HEAD libimobiledevice
brew install ideviceinstaller
✗ ios-deploy not installed. To install:
brew install ios-deploy
✗ CocoaPods not installed.
CocoaPods is used to retrieve the iOS platform side's plugin code that responds to your plugin usage on the Dart side.
Without resolving iOS dependencies with CocoaPods, plugins will not work on iOS.
For more info, see https://flutter.io/platform-plugins
To install:
brew install cocoapods
pod setup

[✓] Android Studio (version 3.0)
• Android Studio at /Applications/Android Studio.app/Contents
• Java version OpenJDK Runtime Environment (build 1.8.0_152-release-915-b08)

[✓] IntelliJ IDEA Community Edition (version 2017.3.3)
• Flutter plugin version 21.1.3
• Dart plugin version 173.4301.22

[-] Connected devices
• None

Start by reproducing the freeze through IntelliJ's Tools → Android → SDK Manager after selecting an already downloaded SDK, using the reported macOS and Android SDK versions as context. Trace the component-download setup flow and verify that the window can be cancelled or closed when the SDK is already up to date.

Written by the indexing model from the issue text.