@hassancs91,
This option doesn't have any relation to your problem. Now I see what are you talking about. These are not the reply nesting issue, these are the "quote" nesting issue.
1. Your forum width is too small. So you should expect this result. This is your choice. Make your forum wider and blockquote text smaller with this CSS code. Insert this CSS code in Dashboard > Forums > Settings > Styles > Custom CSS Code textarea, save it, delete all caches, go to forum front-end and press Ctrl+F5:
.wpforo div.left-content {
border-right: 1px solid #e5e5e5;
margin-right: 0;
padding: 50px 20px;
}
#wpforo #wpforo-wrap .wpforo-post blockquote,
#wpforo #wpforo-wrap .wpforo-revision-body blockquote {
width: 100% !important;
}
#wpforo #wpforo-wrap .wpforo-post blockquote::before {
width: 2px;
border-radius: 0;
}
#wpforo #wpforo-wrap .wpforo-post .wpforo-post-quote-author,
#wpforo #wpforo-wrap .wpforo-revision-body .wpforo-post-quote-author {
padding: 1px 0 !important;
}
#wpforo #wpforo-wrap .wpforo-post .wpforo-post-content blockquote p,
#wpforo #wpforo-wrap .wpforo-revision-body blockquote p {
font-size: 13px !important;
line-height: 18px !important;
}
2. Why your forum users quote so much? They can reply instead of quote. I think the issue is in the forum layout you're currently using. As far as I see, you're using the Extended forum layout. Check out the threaded forum layout, it shows the reply thread and people don't have to quote to see the thread of replies. If your users like to quote, then you should use the Threaded layout: https://wpforo.com/docs/root/categories-and-forums/forum-layouts/threaded-layout/
IMPORTANT: The threaded layout will change your forum home page and forum list as well. It won't look like a classic forum. Here is the Threaded layout forum home page: