I downloaded the new Eclipse Luna (ver. 4.4) and changed to Dark Theme, but the code editor is not changing. See the screen-shot:
I tried this on MAC, Windows and Linux, always the same result.
Ok here's what worked for me. (on java 8 JRE on WinXP)
Preferences -> General -> Editors -> Text Editors: Background colour
deselect 'system default' and choose pure black
Now go to 'current line highlight' and make it your favourite shade of grey. RGB 60/60/60 works for me.