Plugin for IntelliJ, and other Jetbrains products, that lets you duplicate the entire selected lines, not just down (like you already can by default), but also up. In both cases, unlike the default action, it will preserve the original selection after the duplication.
Supports single lines, multiple selected lines, multiple carets and block selection.
Default shortcuts are "Shift + Ctrl + Alt + Up/Down" and "Shift + Command + Option + Up/Down" for macOS.
Compatible with IntelliJ IDEA, PhpStorm, WebStorm, PyCharm, RubyMine, AppCode, CLion, Gogland, DataGrip, Rider, MPS and Android Studio.