Problem: The default keyboard shortcut for duplicating lines (ALT + CTRL + Up/Down) does not work
Configuration: Ubuntu Jaunty, Eclipse 3.5
This is caused by the system using the same shortcuts to move to a virtual workspace above and below. Go to System > Preferences > Keyboard Shortcuts and assign a different key combo for the following two actions:
Switch to workspace up
Switch to workspace down
Duplicate lines works again.