diff --git a/htdocs/core/lib/functions.lib.php b/htdocs/core/lib/functions.lib.php
index 94f4d238ee3..69b414b6078 100644
--- a/htdocs/core/lib/functions.lib.php
+++ b/htdocs/core/lib/functions.lib.php
@@ -7872,7 +7872,10 @@ function printCommonFooter($zone = 'private')
 								// Add property 'required' on input
 								print 'jQuery("input[name=\''.$paramkey.'\']").prop(\'required\',true);'."\n";
 								print 'jQuery("textarea[name=\''.$paramkey.'\']").prop(\'required\',true);'."\n";
-								print 'jQuery("select[name=\''.$paramkey.'\']").prop(\'required\',true);'."\n"; // required on a select works only if key is "", this does not happen in Dolibarr
+								print '// required on a select works only if key is "", so we add the required attributes but also we reset the key -1 or 0 to an empty string'."\n";
+								print 'jQuery("select[name=\''.$paramkey.'\']").prop(\'required\',true);'."\n";
+								print 'jQuery("select[name=\''.$paramkey.'\'] option[value=\'-1\']").prop(\'value\', \'\');'."\n";
+								print 'jQuery("select[name=\''.$paramkey.'\'] option[value=\'0\']").prop(\'value\', \'\');'."\n";
 							}
 						}
 					}
diff --git a/htdocs/langs/en_US/admin.lang b/htdocs/langs/en_US/admin.lang
index de7b0e704b4..c2db3b4f249 100644
--- a/htdocs/langs/en_US/admin.lang
+++ b/htdocs/langs/en_US/admin.lang
@@ -1987,7 +1987,7 @@ SocialNetworkSetup=Setup of module Social Networks
 EnableFeatureFor=Enable features for <strong>%s</strong>
 VATIsUsedIsOff=Note: The option to use Sales Tax or VAT has been set to <strong>Off</strong> in the menu %s - %s, so Sales tax or Vat used will always be 0 for sales.
 SwapSenderAndRecipientOnPDF=Swap sender and recipient address position on PDF documents
-FeatureSupportedOnTextFieldsOnly=Warning, feature supported on text fields only. Also an URL parameter action=create or action=edit must be set OR page name must end with 'new.php' to trigger this feature.
+FeatureSupportedOnTextFieldsOnly=Warning, feature supported on text fields and combo lists only. Also an URL parameter action=create or action=edit must be set OR page name must end with 'new.php' to trigger this feature.
 EmailCollector=Email collector
 EmailCollectorDescription=Add a scheduled job and a setup page to scan regularly email boxes (using IMAP protocol) and record emails received into your application, at the right place and/or create some records automatically (like leads).
 NewEmailCollector=New Email Collector