Eclipse Luna displaying regular scrollbars instead of overlay scrollbars - how to change?

If you're using Ubuntu 12.04 or 14.04, you need to start Eclipse with an env var to force overlay scrollbars:

env LIBOVERLAY_SCROLLBAR=1 eclipse

As I'm using a downloaded Eclipse (and not the one provided by apt), I've created a Eclipse.desktop file (under ~/.local/share/applications/) with the following content (remember to replace <path_to_eclipse_folder> by your path to Eclipse:

#!/usr/bin/env xdg-open

[Desktop Entry]
Version=1.0
Type=Application
Name=Eclipse
Comment=Integrated IDE
Icon=eclipse.png
Exec=env LIBOVERLAY_SCROLLBAR=1 /<path_to_eclipse_folder>/eclipse
Categories=Application;Development;Java;PHP;IDE;
Type=Application
Terminal=false