In this PNFPB plugin I am using default wordpress jquery-ui-dialog style using wp_enqueue_style( ‘wp-jquery-ui-dialog’ ); it is using it from WordPress core. I think rtmedia is using ui-icon trying to override this style. In order to fix in your site, in admin page -> appearence -> customize -> additional css (in additional css) section add below style and refresh the page/cache, it will fix the problem. I have also attached screenshot how to add below style in customize. Since this problem is not related to the plugin, it is difficult for me to fix in this plugin because i am using WordPress core default jquery-ui-dialog style.
