diff --git a/htdocs/admin/pdf.php b/htdocs/admin/pdf.php
index d5873e2a50e..cee63fd91fd 100644
--- a/htdocs/admin/pdf.php
+++ b/htdocs/admin/pdf.php
@@ -52,22 +52,22 @@ if ($cancel) {
 }
 
 if ($action == 'update') {
-	dolibarr_set_const($db, "MAIN_PDF_FORMAT", GETPOST("MAIN_PDF_FORMAT"), 'chaine', 0, '', $conf->entity);
+	if (GETPOSTISSET('MAIN_PDF_FORMAT')) dolibarr_set_const($db, "MAIN_PDF_FORMAT", GETPOST("MAIN_PDF_FORMAT"), 'chaine', 0, '', $conf->entity);
 
-	dolibarr_set_const($db, "MAIN_PDF_MARGIN_LEFT", GETPOST("MAIN_PDF_MARGIN_LEFT"), 'chaine', 0, '', $conf->entity);
-	dolibarr_set_const($db, "MAIN_PDF_MARGIN_RIGHT", GETPOST("MAIN_PDF_MARGIN_TOP"), 'chaine', 0, '', $conf->entity);
-	dolibarr_set_const($db, "MAIN_PDF_MARGIN_BOTTOM", GETPOST("MAIN_PDF_MARGIN_BOTTOM"), 'chaine', 0, '', $conf->entity);
+	if (GETPOSTISSET('MAIN_PDF_MARGIN_LEFT')) dolibarr_set_const($db, "MAIN_PDF_MARGIN_LEFT", GETPOST("MAIN_PDF_MARGIN_LEFT"), 'chaine', 0, '', $conf->entity);
+	if (GETPOSTISSET('MAIN_PDF_MARGIN_RIGHT')) dolibarr_set_const($db, "MAIN_PDF_MARGIN_RIGHT", GETPOST("MAIN_PDF_MARGIN_TOP"), 'chaine', 0, '', $conf->entity);
+	if (GETPOSTISSET('MAIN_PDF_MARGIN_BOTTOM')) dolibarr_set_const($db, "MAIN_PDF_MARGIN_BOTTOM", GETPOST("MAIN_PDF_MARGIN_BOTTOM"), 'chaine', 0, '', $conf->entity);
 
-	dolibarr_set_const($db, "MAIN_PROFID1_IN_ADDRESS", GETPOST("MAIN_PROFID1_IN_ADDRESS"), 'chaine', 0, '', $conf->entity);
-	dolibarr_set_const($db, "MAIN_PROFID2_IN_ADDRESS", GETPOST("MAIN_PROFID2_IN_ADDRESS"), 'chaine', 0, '', $conf->entity);
-	dolibarr_set_const($db, "MAIN_PROFID3_IN_ADDRESS", GETPOST("MAIN_PROFID3_IN_ADDRESS"), 'chaine', 0, '', $conf->entity);
-	dolibarr_set_const($db, "MAIN_PROFID4_IN_ADDRESS", GETPOST("MAIN_PROFID4_IN_ADDRESS"), 'chaine', 0, '', $conf->entity);
-	dolibarr_set_const($db, "MAIN_PROFID5_IN_ADDRESS", GETPOST("MAIN_PROFID5_IN_ADDRESS"), 'chaine', 0, '', $conf->entity);
-	dolibarr_set_const($db, "MAIN_PROFID6_IN_ADDRESS", GETPOST("MAIN_PROFID6_IN_ADDRESS"), 'chaine', 0, '', $conf->entity);
+	if (GETPOSTISSET('MAIN_PROFID1_IN_ADDRESS')) dolibarr_set_const($db, "MAIN_PROFID1_IN_ADDRESS", GETPOST("MAIN_PROFID1_IN_ADDRESS"), 'chaine', 0, '', $conf->entity);
+	if (GETPOSTISSET('MAIN_PROFID2_IN_ADDRESS')) dolibarr_set_const($db, "MAIN_PROFID2_IN_ADDRESS", GETPOST("MAIN_PROFID2_IN_ADDRESS"), 'chaine', 0, '', $conf->entity);
+	if (GETPOSTISSET('MAIN_PROFID3_IN_ADDRESS')) dolibarr_set_const($db, "MAIN_PROFID3_IN_ADDRESS", GETPOST("MAIN_PROFID3_IN_ADDRESS"), 'chaine', 0, '', $conf->entity);
+	if (GETPOSTISSET('MAIN_PROFID4_IN_ADDRESS')) dolibarr_set_const($db, "MAIN_PROFID4_IN_ADDRESS", GETPOST("MAIN_PROFID4_IN_ADDRESS"), 'chaine', 0, '', $conf->entity);
+	if (GETPOSTISSET('MAIN_PROFID5_IN_ADDRESS')) dolibarr_set_const($db, "MAIN_PROFID5_IN_ADDRESS", GETPOST("MAIN_PROFID5_IN_ADDRESS"), 'chaine', 0, '', $conf->entity);
+	if (GETPOSTISSET('MAIN_PROFID6_IN_ADDRESS')) dolibarr_set_const($db, "MAIN_PROFID6_IN_ADDRESS", GETPOST("MAIN_PROFID6_IN_ADDRESS"), 'chaine', 0, '', $conf->entity);
 
-	dolibarr_set_const($db, "MAIN_GENERATE_DOCUMENTS_WITHOUT_VAT", GETPOST("MAIN_GENERATE_DOCUMENTS_WITHOUT_VAT"), 'chaine', 0, '', $conf->entity);
+	if (GETPOSTISSET('MAIN_GENERATE_DOCUMENTS_WITHOUT_VAT')) dolibarr_set_const($db, "MAIN_GENERATE_DOCUMENTS_WITHOUT_VAT", GETPOST("MAIN_GENERATE_DOCUMENTS_WITHOUT_VAT"), 'chaine', 0, '', $conf->entity);
 
-	dolibarr_set_const($db, "MAIN_TVAINTRA_NOT_IN_ADDRESS", GETPOST("MAIN_TVAINTRA_NOT_IN_ADDRESS"), 'chaine', 0, '', $conf->entity);
+	if (GETPOSTISSET('MAIN_TVAINTRA_NOT_IN_ADDRESS')) dolibarr_set_const($db, "MAIN_TVAINTRA_NOT_IN_ADDRESS", GETPOST("MAIN_TVAINTRA_NOT_IN_ADDRESS"), 'chaine', 0, '', $conf->entity);
 
 	if (!empty($conf->projet->enabled)) {
 		if (GETPOST('PDF_SHOW_PROJECT_REF_OR_LABEL') == 'no') {
@@ -82,20 +82,20 @@ if ($action == 'update') {
 		}
 	}
 
-	dolibarr_set_const($db, "MAIN_GENERATE_DOCUMENTS_HIDE_DETAILS", GETPOST("MAIN_GENERATE_DOCUMENTS_HIDE_DETAILS"), 'chaine', 0, '', $conf->entity);
-	dolibarr_set_const($db, "MAIN_GENERATE_DOCUMENTS_HIDE_DESC", GETPOST("MAIN_GENERATE_DOCUMENTS_HIDE_DESC"), 'chaine', 0, '', $conf->entity);
-	dolibarr_set_const($db, "MAIN_GENERATE_DOCUMENTS_HIDE_REF", GETPOST("MAIN_GENERATE_DOCUMENTS_HIDE_REF"), 'chaine', 0, '', $conf->entity);
+	if (GETPOSTISSET('MAIN_GENERATE_DOCUMENTS_HIDE_DETAILS')) dolibarr_set_const($db, "MAIN_GENERATE_DOCUMENTS_HIDE_DETAILS", GETPOST("MAIN_GENERATE_DOCUMENTS_HIDE_DETAILS"), 'chaine', 0, '', $conf->entity);
+	if (GETPOSTISSET('MAIN_GENERATE_DOCUMENTS_HIDE_DESC')) dolibarr_set_const($db, "MAIN_GENERATE_DOCUMENTS_HIDE_DESC", GETPOST("MAIN_GENERATE_DOCUMENTS_HIDE_DESC"), 'chaine', 0, '', $conf->entity);
+	if (GETPOSTISSET('MAIN_GENERATE_DOCUMENTS_HIDE_REF')) dolibarr_set_const($db, "MAIN_GENERATE_DOCUMENTS_HIDE_REF", GETPOST("MAIN_GENERATE_DOCUMENTS_HIDE_REF"), 'chaine', 0, '', $conf->entity);
 
-	dolibarr_set_const($db, "MAIN_DOCUMENTS_LOGO_HEIGHT", GETPOST("MAIN_DOCUMENTS_LOGO_HEIGHT", 'int'), 'chaine', 0, '', $conf->entity);
-	dolibarr_set_const($db, "MAIN_INVERT_SENDER_RECIPIENT", GETPOST("MAIN_INVERT_SENDER_RECIPIENT"), 'chaine', 0, '', $conf->entity);
-	dolibarr_set_const($db, "MAIN_PDF_USE_ISO_LOCATION", GETPOST("MAIN_PDF_USE_ISO_LOCATION"), 'chaine', 0, '', $conf->entity);
-	dolibarr_set_const($db, "MAIN_GENERATE_DOCUMENTS_SHOW_FOOT_DETAILS", GETPOST("MAIN_GENERATE_DOCUMENTS_SHOW_FOOT_DETAILS"), 'chaine', 0, '', $conf->entity);
+	if (GETPOSTISSET('MAIN_DOCUMENTS_LOGO_HEIGHT')) dolibarr_set_const($db, "MAIN_DOCUMENTS_LOGO_HEIGHT", GETPOST("MAIN_DOCUMENTS_LOGO_HEIGHT", 'int'), 'chaine', 0, '', $conf->entity);
+	if (GETPOSTISSET('MAIN_INVERT_SENDER_RECIPIENT')) dolibarr_set_const($db, "MAIN_INVERT_SENDER_RECIPIENT", GETPOST("MAIN_INVERT_SENDER_RECIPIENT"), 'chaine', 0, '', $conf->entity);
+	if (GETPOSTISSET('MAIN_PDF_USE_ISO_LOCATION')) dolibarr_set_const($db, "MAIN_PDF_USE_ISO_LOCATION", GETPOST("MAIN_PDF_USE_ISO_LOCATION"), 'chaine', 0, '', $conf->entity);
+	if (GETPOSTISSET('MAIN_GENERATE_DOCUMENTS_SHOW_FOOT_DETAILS')) dolibarr_set_const($db, "MAIN_GENERATE_DOCUMENTS_SHOW_FOOT_DETAILS", GETPOST("MAIN_GENERATE_DOCUMENTS_SHOW_FOOT_DETAILS"), 'chaine', 0, '', $conf->entity);
 
-	dolibarr_set_const($db, "MAIN_PDF_MAIN_HIDE_SECOND_TAX", GETPOST("MAIN_PDF_MAIN_HIDE_SECOND_TAX"), 'chaine', 0, '', $conf->entity);
-	dolibarr_set_const($db, "MAIN_PDF_MAIN_HIDE_THIRD_TAX", GETPOST("MAIN_PDF_MAIN_HIDE_THIRD_TAX"), 'chaine', 0, '', $conf->entity);
+	if (GETPOSTISSET('MAIN_PDF_MAIN_HIDE_SECOND_TAX')) dolibarr_set_const($db, "MAIN_PDF_MAIN_HIDE_SECOND_TAX", GETPOST("MAIN_PDF_MAIN_HIDE_SECOND_TAX"), 'chaine', 0, '', $conf->entity);
+	if (GETPOSTISSET('MAIN_PDF_MAIN_HIDE_THIRD_TAX')) dolibarr_set_const($db, "MAIN_PDF_MAIN_HIDE_THIRD_TAX", GETPOST("MAIN_PDF_MAIN_HIDE_THIRD_TAX"), 'chaine', 0, '', $conf->entity);
 
-	dolibarr_set_const($db, "PDF_USE_ALSO_LANGUAGE_CODE", GETPOST('PDF_USE_ALSO_LANGUAGE_CODE', 'alpha'), 'chaine', 0, '', $conf->entity);
-	dolibarr_set_const($db, "SHOW_SUBPRODUCT_REF_IN_PDF", GETPOST('SHOW_SUBPRODUCT_REF_IN_PDF', 'alpha'), 'chaine', 0, '', $conf->entity);
+	if (GETPOSTISSET('PDF_USE_ALSO_LANGUAGE_CODE')) dolibarr_set_const($db, "PDF_USE_ALSO_LANGUAGE_CODE", GETPOST('PDF_USE_ALSO_LANGUAGE_CODE', 'alpha'), 'chaine', 0, '', $conf->entity);
+	if (GETPOSTISSET('SHOW_SUBPRODUCT_REF_IN_PDF')) dolibarr_set_const($db, "SHOW_SUBPRODUCT_REF_IN_PDF", GETPOST('SHOW_SUBPRODUCT_REF_IN_PDF', 'alpha'), 'chaine', 0, '', $conf->entity);
 
 	setEventMessages($langs->trans("SetupSaved"), null, 'mesgs');