diff --git a/htdocs/user/agenda_extsites.php b/htdocs/user/agenda_extsites.php
index 3bd0468cc27..3faf6dc770c 100644
--- a/htdocs/user/agenda_extsites.php
+++ b/htdocs/user/agenda_extsites.php
@@ -174,7 +174,7 @@ print '<br>';
 print '<span class="opacitymedium">'.$langs->trans("AgendaExtSitesDesc")."</span><br>\n";
 print "<br>\n";
 
-$selectedvalue = $conf->global->AGENDA_DISABLE_EXT;
+$selectedvalue = empty($conf->global->AGENDA_DISABLE_EXT) ? 0 : $conf->global->AGENDA_DISABLE_EXT;
 if ($selectedvalue == 1) {
 	$selectedvalue = 0;
 } else {
@@ -201,20 +201,23 @@ while ($i <= $MAXAGENDA) {
 	$offsettz = 'AGENDA_EXT_OFFSETTZ_'.$id.'_'.$key;
 	$color = 'AGENDA_EXT_COLOR_'.$id.'_'.$key;
 
-
 	print '<tr class="oddeven">';
 	// Nb
 	print '<td class="maxwidth50onsmartphone">'.$langs->trans("AgendaExtNb", $key)."</td>";
 	// Name
-	print '<td class="maxwidth50onsmartphone"><input type="text" class="flat hideifnotset minwidth100" name="AGENDA_EXT_NAME_'.$id.'_'.$key.'" value="'.(GETPOST('AGENDA_EXT_NAME_'.$id.'_'.$key) ?GETPOST('AGENDA_EXT_NAME_'.$id.'_'.$key) : $object->conf->$name).'"></td>';
+	$name_value = (GETPOST('AGENDA_EXT_NAME_'.$id.'_'.$key) ?GETPOST('AGENDA_EXT_NAME_'.$id.'_'.$key) : (empty($object->conf->$name) ? '' : $object->conf->$name));
+	print '<td class="maxwidth50onsmartphone"><input type="text" class="flat hideifnotset minwidth100" name="AGENDA_EXT_NAME_'.$id.'_'.$key.'" value="'.$name_value.'"></td>';
 	// URL
-	print '<td class="maxwidth50onsmartphone"><input type="url" class="flat hideifnotset" name="AGENDA_EXT_SRC_'.$id.'_'.$key.'" value="'.(GETPOST('AGENDA_EXT_SRC_'.$id.'_'.$key) ?GETPOST('AGENDA_EXT_SRC_'.$id.'_'.$key) : $object->conf->$src).'"></td>';
+	$src_value = (GETPOST('AGENDA_EXT_SRC_'.$id.'_'.$key) ?GETPOST('AGENDA_EXT_SRC_'.$id.'_'.$key) : (empty($object->conf->$src) ? '' : $object->conf->$src));
+	print '<td class="maxwidth50onsmartphone"><input type="url" class="flat hideifnotset" name="AGENDA_EXT_SRC_'.$id.'_'.$key.'" value="'.$src_value.'"></td>';
 	// Offset TZ
-	print '<td><input type="text" class="flat hideifnotset" name="AGENDA_EXT_OFFSETTZ_'.$id.'_'.$key.'" value="'.(GETPOST('AGENDA_EXT_OFFSETTZ_'.$id.'_'.$key) ?GETPOST('AGENDA_EXT_OFFSETTZ_'.$id.'_'.$key) : $object->conf->$offsettz).'" size="1"></td>';
+	$offsettz_value = (GETPOST('AGENDA_EXT_OFFSETTZ_'.$id.'_'.$key) ? GETPOST('AGENDA_EXT_OFFSETTZ_'.$id.'_'.$key) : (empty($object->conf->$offsettz) ? 0 : $object->conf->$offsettz));
+	print '<td><input type="text" class="flat hideifnotset" name="AGENDA_EXT_OFFSETTZ_'.$id.'_'.$key.'" value="'.$offsettz_value.'" size="1"></td>';
 	// Color (Possible colors are limited by Google)
 	print '<td class="nowrap right">';
 	//print $formadmin->selectColor($conf->global->$color, "google_agenda_color".$key, $colorlist);
-	print $formother->selectColor((GETPOST("AGENDA_EXT_COLOR_".$id.'_'.$key) ?GETPOST("AGENDA_EXT_COLOR_".$id.'_'.$key) : $object->conf->$color), "AGENDA_EXT_COLOR_".$id.'_'.$key, 'extsitesconfig', 1, '', 'hideifnotset');
+	$color_value = (GETPOST("AGENDA_EXT_COLOR_".$id.'_'.$key) ?GETPOST("AGENDA_EXT_COLOR_".$id.'_'.$key) : (empty($object->conf->$color) ? 'ffffff' : $object->conf->$color));
+	print $formother->selectColor($color_value, "AGENDA_EXT_COLOR_".$id.'_'.$key, 'extsitesconfig', 1, '', 'hideifnotset');
 	print '</td>';
 	print "</tr>";
 	$i++;