Use bueditor to edit panel custom content for D7

the same issue for D7 should be fixed by the same code but with another path condition:

if (arg(0) == 'admin' && arg(1) == 'structure' && arg(2) == 'pages' && module_exists('bueditor')) {
  $bue_id = 1;//your editor's id
  bueditor_settle($bue_id);
  $bue_setting['BUE']['preset']['edit-body'] = "e$bue_id";
  drupal_add_js($bue_setting, 'setting');
  drupal_set_html_head('<style type="text/css">.bue-popup{z-index: 1001 !important}</style>');
}