The bidi.css file contains padding, background and position rules which are added to the li.row subforum class.

This makes the space between the subforums too big when using an RTL language.

The LTR version doesn't have this rule so it must have been left over from changes in the past.

File:

bidi.css

Delete:

.rtl ul.topiclist li.row dt a.subforum {

    padding-right: 12px;

    background-position: right;

    position: static;

}