I believe this setting might be causing IntelliJ IDEA to behave slowly. I used to get a popup and finally clicked \'do this automatically\', and now it is on, but I want to
For me (IntelliJ IDEA 14.1.1 on Ubuntu 12) this setting was in Settings > Build, Execution, Deployment > Build Tools > Maven > Importing > [X] Import Maven projects automatically.
In case it moves again, or you want to get to it quickly, the Maven settings are also findable through a general search by double-tapping Shift and then typing maven, which is how I found it this time--I think the setting location in IDEA must have been moved since the other answers were posted.