When formatting the following code
SELECT -- part 1
:var1 AS var1,
:var2 AS var2,
-- part 2
:var3 AS var3,
:var4 AS var4,
:var5 AS var5,
-- part 3
:var6 AS var6,
:var7 AS var7,
:var8 AS var8
FROM DUAL;
the line after each comment (except the first one) is offset by one space.
The formatter options for comments are set to: