How do I get rid of the <select> element diagram in Firefox?

Question

So, here is a fiddle demonstrating the problem: http://jsfiddle.net/CVTrb/1/ , select and choose any option, and then you will see a thin gray color of a line that is definitely not in the element <select>.

Here is an image showing this:

:

Answer 1

Credit for this post here: fooobar.com/questions/78086 / ...

select:-moz-focusring {
    color: transparent;
    text-shadow: 0 0 0 #000;
}

Answer 2

Add outline: none;to.form-dropdown

Answer 3

:
,

select:-moz-focusring {
    color: transparent;  /* hides that darn border... and the options */
    text-shadow: 0 0 0 #000;   /* "unhide" the options */
}
select:-moz-focusring option:disabled {
    text-shadow: none;     /* remove the inherited shadow from disabled options */
}