When using an RTL language the back to top button on posts has a margin applied to both sides of it.

This is due to a missing rule in the bidi.css file, the bidi file usually removes the margin from one side and adds it to the other but for this rule it has added the margin to one side but hasn't removed it from the other.

File:

bidi.css

Find:

.rtl .back2top .top {

    float: left;

    margin-left: -10px;

}

Change To:

.rtl .back2top .top {

    float: left;

    margin-right: 0;

    margin-left: -10px;

}