When exploring a code, sometimes you end up in a decompiled code from a JAR for which there's no source code attached. Previously you had to: 1. go find the source JAR on the Web 2. download it to your disk 3. go to your project structure settings 4. attach the JAR to the library of interest A bit too much, isn't it? Now (in the next EAP) IntelliJ IDEA 11 does it all for you:

Meeting the needs of developers working with JavaScript, Intellij IDEA 10 adds a new feature to allow specifying global JavaScript libraries that can be used across multiple projects. For a particular project you can set a scope for each library by defining files and directories the library is applicable to. If you already have JavaScript files in your project and keep your current settings, code completion and navigation would work as before. (more…)