styles.css

    
#open-files-container a.working-set-related-link {
    display:none;
    height: 16px;
    padding-right: 4px;
    margin-right: 0px;
    line-height: 18px;
}
    
#open-files-container li.selected.has-related-files:hover a.working-set-related-link, #open-files-container li.selected.has-related-files.related-opened a.working-set-related-link {
    display:block;
    position: absolute;
    top:0px;
    right: 10px;
    color:#efefef;
    cursor:pointer;
}
    
#open-files-container li.selected.has-related-files.related-opened a.working-set-related-link {
    -webkit-transform-origin: 20% 60%;
    -webkit-transform: rotate(270deg);
}
    
    
#open-files-container li.selected .working-set-related-files {
    display:block;
}
    
#open-files-container .working-set-related-files {
    display:none;
    background-color: rgba(0,0,0,0.3);
    margin-left:-8px;
}

#open-files-container .working-set-related-files a {
    color:#CCC;
    font-size:0.9em;
    padding-left:18px;
    cursor:pointer;
}
        
#open-files-container .working-set-related-files a:hover {
    color:#EFEFEF;
}

#open-files-container.vertical-scroll li.selected.has-related-files:hover a.working-set-related-link, #open-files-container.vertical-scroll li.selected.has-related-files.related-opened a.working-set-related-link {
    right:0px;
}