FCKEditor adds CSS style code to output

Hi,

I am using FCK in a CMS and everytime FCK opens the following CSS is added.

<style type="text/css">span.fon_container{
    height:15px !important;
    white-space: nowrap !important;
}
span.fon_flag{
    background: url(chrome://fon/skin/mflag.gif) no-repeat right;
    height:15px !important;
    padding:0px 0px 2px 5px !important;
    cursor: pointer;
}
span.fon_noflag{
    background: url(images/mflag.gif) no-repeat left;
    height:15px !important;
    padding:0px 0px 2px 5px !important;
    cursor: pointer;
}
span.fon_flag_a{
    background-image: url(chrome://fon/skin/mflag_a.gif);
}
img.fon_flag {
    margin-bottom:2px !important;
    vertical-align: middle !important;
}
span.fon_phone {
    background: url(chrome://fon/skin/mmid.gif) repeat-x center;
    height:15px !important;
    padding:0px 2px 2px 2px !important;
    cursor: pointer;
}
span.fon_phone_a {
    background-image: url(chrome://fon/skin/mmid_a.gif);
}
span.fon_phone_inner {
    color: black !important;
    text-decoration: none !important;
    font-family: Verdana !important;
    font-size: 11px !important;
    font-weight: bold !important;
}
span.fon_arrow {
    background: url(chrome://fon/skin/marrow.gif) no-repeat left;
    display: inline !important;
    height:15px !important;
    padding:0px 10px 2px 0px !important;
}
span.fon_arrow_a {
    background-image: url(chrome://fon/skin/marrow_a.gif);
}
</style>

After a few updates the resulting code gets really long as it is added everytime.

Does anybody know why?

Thanks,

Glen