Settings | Editor | Appearance | Show method separators -- this will remove lines above functions
For lines before namespace/class -- they cannot be removed (AFAIK) .. but you can change the color (make them invisible) -- "Settings | Editor | Colors & Fonts | General | Method separator color"
"Settings | Editor | Colors & Fonts | General | Method separator color" -- works perfectly for me
Instead of specifying color (which still works) you can just untick the check box against "Foreground" -- should have the same effect:
They are for visually separating one function/method/class/namespace from another.
I, personally, do like it a lot as I do not need to use separate line with comment (something like /*********/) to make such separation.
But it is true that not everyone likes it -- that's why you can make them invisible by setting color the same as background (or removing checkbox -- either should work -- at least works for me).
Aha! Here is the problem.
It doesn't seems obvious for me since almost all personalizations are immediately applied just clicking on the "apply" button.
Thanks so much for you time.