@dima,

Your screenshot  says nothing. What is the problem?

In any case, please replace the previous CSS code to this one:

#wpforo #wpforo-wrap .wpfl-1 .wpforo-post .wpf-left {
  display: none;
}
#wpforo #wpforo-wrap .wpfl-1 .wpforo-post .wpf-right {
  margin-left: 0 !important;
}