 <p>You will run into the same problem when using a Bootstrap theme beside the one in Extlib / BS4XPages plugin. In that case I don't use the minified CSS and edit it, commenting out the part where the glyphicons generally are defined (references to the font resources). As the icons are the same in every theme you can get this won't do any harm and the icons keep working. Some themes don't have the Glyphicon stuff in it and contain just additional CSS information for colors etc. In that case there is no problem with icons.</p>