code: protected String getSelectorUrl() {
  
          StringBuffer result = new StringBuffer(128);
          result.append(CmsCoreProvider.get().link("/system/workplace/views/explorer/tree_fs.jsp"));
          result.append("?type=vfswidget&includefiles=true&showsiteselector=true&projectaware=false&treesite=");
          result.append(CmsCoreProvider.get().getSiteRoot());
          return result.toString();
      }
docs: Returns the URL to the link selector popup.<p>
  
  @return the URL to the link selector popup