If you hit retutn midway through a css decleration, without completing it then that line will become invalid, and the browser rendering engine will move to the next decleration. So Dw moving to a new property would be expected.
Or is Dw doing this line break action itself?
Edit: before anyone says it yes i know the next line would also be invalid.
Are you asking why you are allowed to enter invalid css?
If so, all code editors do, it is for the user to know what is valid and what is not. As an example in visual studio, i can enter the following in a css file -
(
h
e
i
g
h
t;
}
completely invalid, but i can enter it.
The error checker, or linter should catch the error, but nothing will stop a user doing so.