diff --git a/htdocs/comm/propal.php b/htdocs/comm/propal.php
index 6cd70b273be..5d1db5cf7d1 100644
--- a/htdocs/comm/propal.php
+++ b/htdocs/comm/propal.php
@@ -186,7 +186,7 @@ else if ($action == 'confirm_validate' && $confirm == 'yes' && $user->rights->pr
 }
 
 else if ($action == 'setdate' && $user->rights->propal->creer) {
-	$datep = dol_mktime(12, 0, 0, $_POST ['remonth'], $_POST ['reday'], $_POST ['reyear']);
+	$datep = dol_mktime(12, 0, 0, $_POST['remonth'], $_POST['reday'], $_POST['reyear']);
 
 	if (empty($datep)) {
 		$error ++;
@@ -199,18 +199,18 @@ else if ($action == 'setdate' && $user->rights->propal->creer) {
 			dol_print_error($db, $object->error);
 	}
 } else if ($action == 'setecheance' && $user->rights->propal->creer) {
-	$result = $object->set_echeance($user, dol_mktime(12, 0, 0, $_POST ['echmonth'], $_POST ['echday'], $_POST ['echyear']));
+	$result = $object->set_echeance($user, dol_mktime(12, 0, 0, $_POST['echmonth'], $_POST['echday'], $_POST['echyear']));
 	if ($result < 0)
 		dol_print_error($db, $object->error);
 } else if ($action == 'setdate_livraison' && $user->rights->propal->creer) {
-	$result = $object->set_date_livraison($user, dol_mktime(12, 0, 0, $_POST ['liv_month'], $_POST ['liv_day'], $_POST ['liv_year']));
+	$result = $object->set_date_livraison($user, dol_mktime(12, 0, 0, $_POST['liv_month'], $_POST['liv_day'], $_POST['liv_year']));
 	if ($result < 0)
 		dol_print_error($db, $object->error);
 }
 
 // Positionne ref client
 else if ($action == 'set_ref_client' && $user->rights->propal->creer) {
-	$object->set_ref_client($user, $_POST ['ref_client']);
+	$object->set_ref_client($user, $_POST['ref_client']);
 }
 
 // Create proposal
@@ -296,11 +296,11 @@ else if ($action == 'add' && $user->rights->propal->creer) {
 
 			for($i = 1; $i <= $conf->global->PRODUCT_SHOW_WHEN_CREATE; $i ++)
 			{
-				if ($_POST ['idprod' . $i]) {
+				if ($_POST['idprod' . $i]) {
 					$xid = 'idprod' . $i;
 					$xqty = 'qty' . $i;
 					$xremise = 'remise' . $i;
-					$object->add_product($_POST [$xid], $_POST [$xqty], $_POST [$xremise]);
+					$object->add_product($_POST[$xid], $_POST[$xqty], $_POST[$xremise]);
 				}
 			}
 
@@ -544,7 +544,7 @@ if (GETPOST('removedfile')) {
 	$upload_dir_tmp = $vardir . '/temp';
 
 	// TODO Delete only files that was uploaded from email form
-	dol_remove_file_process($_POST ['removedfile'], 0);
+	dol_remove_file_process($_POST['removedfile'], 0);
 	$action = 'presend';
 }
 
@@ -555,35 +555,35 @@ if ($action == 'send' && ! GETPOST('addfile') && ! GETPOST('removedfile') && ! G
 	$langs->load('mails');
 
 	if ($object->id > 0) {
-		if ($_POST ['sendto']) {
+		if ($_POST['sendto']) {
 			// Le destinataire a ete fourni via le champ libre
-			$sendto = $_POST ['sendto'];
+			$sendto = $_POST['sendto'];
 			$sendtoid = 0;
-		} elseif ($_POST ['receiver'] != '-1') {
+		} elseif ($_POST['receiver'] != '-1') {
 			// Recipient was provided from combo list
-			if ($_POST ['receiver'] == 'thirdparty') 			// Id of third party
+			if ($_POST['receiver'] == 'thirdparty') 			// Id of third party
 			{
 				$sendto = $object->thirdparty->email;
 				$sendtoid = 0;
 			} else 			// Id du contact
 			{
-				$sendto = $object->thirdparty->contact_get_property($_POST ['receiver'], 'email');
-				$sendtoid = $_POST ['receiver'];
+				$sendto = $object->thirdparty->contact_get_property($_POST['receiver'], 'email');
+				$sendtoid = $_POST['receiver'];
 			}
 		}
 
 		if (dol_strlen($sendto)) {
 			$langs->load("commercial");
 
-			$from = $_POST ['fromname'] . ' <' . $_POST ['frommail'] . '>';
-			$replyto = $_POST ['replytoname'] . ' <' . $_POST ['replytomail'] . '>';
-			$message = $_POST ['message'];
-			$sendtocc = $_POST ['sendtocc'];
+			$from = $_POST['fromname'] . ' <' . $_POST['frommail'] . '>';
+			$replyto = $_POST['replytoname'] . ' <' . $_POST['replytomail'] . '>';
+			$message = $_POST['message'];
+			$sendtocc = $_POST['sendtocc'];
 			$sendtobcc = (empty($conf->global->MAIN_MAIL_AUTOCOPY_PROPOSAL_TO)?'':$conf->global->MAIN_MAIL_AUTOCOPY_PROPOSAL_TO);
-			$deliveryreceipt = $_POST ['deliveryreceipt'];
+			$deliveryreceipt = $_POST['deliveryreceipt'];
 
-			if (dol_strlen($_POST ['subject']))
-				$subject = $_POST ['subject'];
+			if (dol_strlen($_POST['subject']))
+				$subject = $_POST['subject'];
 			else
 				$subject = $langs->transnoentities('Propal') . ' ' . $object->ref;
 			$actiontypecode = 'AC_PROP';
@@ -683,9 +683,9 @@ if ($action == 'modif' && $user->rights->propal->creer)
 }
 
 else if ($action == "setabsolutediscount" && $user->rights->propal->creer) {
-	if ($_POST ["remise_id"]) {
+	if ($_POST["remise_id"]) {
 		if ($object->id > 0) {
-			$result = $object->insert_discount($_POST ["remise_id"]);
+			$result = $object->insert_discount($_POST["remise_id"]);
 			if ($result < 0) {
 				setEventMessage($object->error, 'errors');
 			}
@@ -723,7 +723,7 @@ else if ($action == 'addline' && $user->rights->propal->creer) {
 	if (is_array($extralabelsline)) {
 		// Get extra fields
 		foreach ($extralabelsline as $key => $value) {
-			unset($_POST ["options_" . $key]);
+			unset($_POST["options_" . $key]);
 		}
 	}
 
@@ -895,23 +895,23 @@ else if ($action == 'addline' && $user->rights->propal->creer) {
 					$object->generateDocument($object->modelpdf, $outputlangs, $hidedetails, $hidedesc, $hideref);
 				}
 
-				unset($_POST ['prod_entry_mode']);
+				unset($_POST['prod_entry_mode']);
 
-				unset($_POST ['qty']);
-				unset($_POST ['type']);
-				unset($_POST ['remise_percent']);
-				unset($_POST ['price_ht']);
-				unset($_POST ['price_ttc']);
-				unset($_POST ['tva_tx']);
-				unset($_POST ['product_ref']);
-				unset($_POST ['product_label']);
-				unset($_POST ['product_desc']);
-				unset($_POST ['fournprice']);
-				unset($_POST ['buying_price']);
-				unset($_POST ['np_marginRate']);
-				unset($_POST ['np_markRate']);
-				unset($_POST ['dp_desc']);
-				unset($_POST ['idprod']);
+				unset($_POST['qty']);
+				unset($_POST['type']);
+				unset($_POST['remise_percent']);
+				unset($_POST['price_ht']);
+				unset($_POST['price_ttc']);
+				unset($_POST['tva_tx']);
+				unset($_POST['product_ref']);
+				unset($_POST['product_label']);
+				unset($_POST['product_desc']);
+				unset($_POST['fournprice']);
+				unset($_POST['buying_price']);
+				unset($_POST['np_marginRate']);
+				unset($_POST['np_markRate']);
+				unset($_POST['dp_desc']);
+				unset($_POST['idprod']);
 
 		    	unset($_POST['date_starthour']);
 		    	unset($_POST['date_startmin']);
@@ -966,7 +966,7 @@ else if ($action == 'updateligne' && $user->rights->propal->creer && GETPOST('sa
 	if (is_array($extralabelsline)) {
 		// Get extra fields
 		foreach ($extralabelsline as $key => $value) {
-			unset($_POST ["options_" . $key]);
+			unset($_POST["options_" . $key]);
 		}
 	}
 
@@ -1023,18 +1023,18 @@ else if ($action == 'updateligne' && $user->rights->propal->creer && GETPOST('sa
 				$object->generateDocument($object->modelpdf, $outputlangs, $hidedetails, $hidedesc, $hideref);
 			}
 
-			unset($_POST ['qty']);
-			unset($_POST ['type']);
-			unset($_POST ['productid']);
-			unset($_POST ['remise_percent']);
-			unset($_POST ['price_ht']);
-			unset($_POST ['price_ttc']);
-			unset($_POST ['tva_tx']);
-			unset($_POST ['product_ref']);
-			unset($_POST ['product_label']);
-			unset($_POST ['product_desc']);
-			unset($_POST ['fournprice']);
-			unset($_POST ['buying_price']);
+			unset($_POST['qty']);
+			unset($_POST['type']);
+			unset($_POST['productid']);
+			unset($_POST['remise_percent']);
+			unset($_POST['price_ht']);
+			unset($_POST['price_ttc']);
+			unset($_POST['tva_tx']);
+			unset($_POST['product_ref']);
+			unset($_POST['product_label']);
+			unset($_POST['product_desc']);
+			unset($_POST['fournprice']);
+			unset($_POST['buying_price']);
 		} else {
 			$db->rollback();
 
@@ -1091,17 +1091,17 @@ else if ($action == 'remove_file' && $user->rights->propal->creer) {
 
 // Set project
 else if ($action == 'classin' && $user->rights->propal->creer) {
-	$object->setProject($_POST ['projectid']);
+	$object->setProject($_POST['projectid']);
 }
 
 // Delai de livraison
 else if ($action == 'setavailability' && $user->rights->propal->creer) {
-	$result = $object->availability($_POST ['availability_id']);
+	$result = $object->availability($_POST['availability_id']);
 }
 
 // Origine de la propale
 else if ($action == 'setdemandreason' && $user->rights->propal->creer) {
-	$result = $object->demand_reason($_POST ['demand_reason_id']);
+	$result = $object->demand_reason($_POST['demand_reason_id']);
 }
 
 // Conditions de reglement
@@ -1110,11 +1110,11 @@ else if ($action == 'setconditions' && $user->rights->propal->creer) {
 }
 
 else if ($action == 'setremisepercent' && $user->rights->propal->creer) {
-	$result = $object->set_remise_percent($user, $_POST ['remise_percent']);
+	$result = $object->set_remise_percent($user, $_POST['remise_percent']);
 }
 
 else if ($action == 'setremiseabsolue' && $user->rights->propal->creer) {
-	$result = $object->set_remise_absolue($user, $_POST ['remise_absolue']);
+	$result = $object->set_remise_absolue($user, $_POST['remise_absolue']);
 }
 
 // Mode de reglement
@@ -1206,7 +1206,7 @@ if (! empty($conf->global->MAIN_DISABLE_CONTACTS_TAB) && $user->rights->propal->
 	{
 		if ($object->id > 0) {
 			$contactid = (GETPOST('userid') ? GETPOST('userid') : GETPOST('contactid'));
-			$result = $object->add_contact($contactid, $_POST ["type"], $_POST ["source"]);
+			$result = $object->add_contact($contactid, $_POST["type"], $_POST["source"]);
 		}
 
 		if ($result >= 0) {
diff --git a/htdocs/compta/facture.php b/htdocs/compta/facture.php
index 27dbcc5c83c..1a67ffb2feb 100644
--- a/htdocs/compta/facture.php
+++ b/htdocs/compta/facture.php
@@ -1158,7 +1158,11 @@ else if ($action == 'addline' && $user->rights->facture->creer)
 		setEventMessage($langs->trans('ErrorFieldRequired', $langs->transnoentitiesnoconv('Description')), 'errors');
 		$error ++;
 	}
-
+	if ($qty < 0) {
+		$langs->load("errors");
+		setEventMessage($langs->trans('ErrorQtyForCustomerInvoiceCantBeNegative'), 'errors');
+		$error ++;
+	}
 	if (! $error && ($qty >= 0) && (! empty($product_desc) || ! empty($idprod))) {
 		$ret = $object->fetch($id);
 		if ($ret < 0) {
@@ -1320,7 +1324,7 @@ else if ($action == 'addline' && $user->rights->facture->creer)
 					$object->generateDocument($object->modelpdf, $outputlangs, $hidedetails, $hidedesc, $hideref);
 				}
 
-				unset($_POST ['prod_entry_mode']);
+				unset($_POST['prod_entry_mode']);
 
 				unset($_POST['qty']);
 				unset($_POST['type']);
@@ -1359,9 +1363,9 @@ else if ($action == 'addline' && $user->rights->facture->creer)
 	}
 }
 
-elseif ($action == 'updateligne' && $user->rights->facture->creer && ! GETPOST('cancel')) {
-	if (! $object->fetch($id) > 0)
-		dol_print_error($db);
+elseif ($action == 'updateligne' && $user->rights->facture->creer && ! GETPOST('cancel'))
+{
+	if (! $object->fetch($id) > 0)	dol_print_error($db);
 	$object->fetch_thirdparty();
 
 	// Clean parameters
@@ -1372,6 +1376,7 @@ elseif ($action == 'updateligne' && $user->rights->facture->creer && ! GETPOST('
 	$description = dol_htmlcleanlastbr(GETPOST('product_desc'));
 	$pu_ht = GETPOST('price_ht');
 	$vat_rate = (GETPOST('tva_tx') ? GETPOST('tva_tx') : 0);
+	$qty = GETPOST('qty');
 
 	// Define info_bits
 	$info_bits = 0;
@@ -1428,10 +1433,15 @@ elseif ($action == 'updateligne' && $user->rights->facture->creer && ! GETPOST('
 			$error ++;
 		}
 	}
+	if ($qty < 0) {
+		$langs->load("errors");
+		setEventMessage($langs->trans('ErrorQtyForCustomerInvoiceCantBeNegative'), 'errors');
+		$error ++;
+	}
 
 	// Update line
 	if (! $error) {
-		$result = $object->updateline(GETPOST('lineid'), $description, $pu_ht, GETPOST('qty'), GETPOST('remise_percent'), $date_start, $date_end, $vat_rate, $localtax1_rate, $localtax2_rate, 'HT', $info_bits, $type, GETPOST('fk_parent_line'), 0, $fournprice, $buyingprice, $label, 0, $array_option);
+		$result = $object->updateline(GETPOST('lineid'), $description, $pu_ht, $qty, GETPOST('remise_percent'), $date_start, $date_end, $vat_rate, $localtax1_rate, $localtax2_rate, 'HT', $info_bits, $type, GETPOST('fk_parent_line'), 0, $fournprice, $buyingprice, $label, 0, $array_option);
 
 		if ($result >= 0) {
 			if (empty($conf->global->MAIN_DISABLE_PDF_AUTOUPDATE)) {
@@ -1463,6 +1473,8 @@ elseif ($action == 'updateligne' && $user->rights->facture->creer && ! GETPOST('
 			unset($_POST['product_desc']);
 			unset($_POST['fournprice']);
 			unset($_POST['buying_price']);
+			unset($_POST['np_marginRate']);
+			unset($_POST['np_markRate']);
 		} else {
 			setEventMessage($object->error, 'errors');
 		}
diff --git a/htdocs/langs/en_US/bills.lang b/htdocs/langs/en_US/bills.lang
index 177d82ef5b4..5c16e18e4cf 100644
--- a/htdocs/langs/en_US/bills.lang
+++ b/htdocs/langs/en_US/bills.lang
@@ -28,8 +28,8 @@ InvoiceAvoir=Credit note
 InvoiceAvoirAsk=Credit note to correct invoice
 InvoiceAvoirDesc=The <b>credit note</b> is a negative invoice used to solve fact that an invoice has an amount that differs than amount really paid (because customer paid too much by error, or will not paid completely since he returned some products for example).
 invoiceAvoirWithLines=Create Credit Note with lines from the origin invoice
-invoiceAvoirWithPaymentRestAmount=Create Credit Note with the amount of origin invoice payment's lake 
-invoiceAvoirLineWithPaymentRestAmount=Credit Note amount of invoice payment's lake
+invoiceAvoirWithPaymentRestAmount=Create Credit Note with remaining unpaid of origin invoice 
+invoiceAvoirLineWithPaymentRestAmount=Credit Note for remaining unpaid amount
 ReplaceInvoice=Replace invoice %s
 ReplacementInvoice=Replacement invoice
 ReplacedByInvoice=Replaced by invoice %s
@@ -99,7 +99,7 @@ DoPaymentBack=Do payment back
 ConvertToReduc=Convert into future discount
 EnterPaymentReceivedFromCustomer=Enter payment received from customer
 EnterPaymentDueToCustomer=Make payment due to customer
-DisabledBecauseRemainderToPayIsZero=Disabled because remainder to pay is zero
+DisabledBecauseRemainderToPayIsZero=Disabled because remaining unpaid is zero
 Amount=Amount
 PriceBase=Price base
 BillStatus=Invoice status
@@ -156,9 +156,9 @@ ConfirmCancelBill=Are you sure you want to cancel invoice <b>%s</b> ?
 ConfirmCancelBillQuestion=Why do you want to classify this invoice 'abandoned' ?
 ConfirmClassifyPaidPartially=Are you sure you want to change invoice <b>%s</b> to status paid ?
 ConfirmClassifyPaidPartiallyQuestion=This invoice has not been paid completely. What are reasons for you to close this invoice ?
-ConfirmClassifyPaidPartiallyReasonAvoir=Remainder to pay <b>(%s %s)</b> is a discount granted because payment was made before term. I regularise the VAT with a credit note.
-ConfirmClassifyPaidPartiallyReasonDiscountNoVat=Remainder to pay <b>(%s %s)</b> is a discount granted because payment was made before term. I accept to lose the VAT on this discount.
-ConfirmClassifyPaidPartiallyReasonDiscountVat=Remainder to pay <b>(%s %s)</b> is a discount granted because payment was made before term. I recover the VAT on this discount without a credit note. 
+ConfirmClassifyPaidPartiallyReasonAvoir=Remaining unpaid <b>(%s %s)</b> is a discount granted because payment was made before term. I regularise the VAT with a credit note.
+ConfirmClassifyPaidPartiallyReasonDiscountNoVat=Remaining unpaid <b>(%s %s)</b> is a discount granted because payment was made before term. I accept to lose the VAT on this discount.
+ConfirmClassifyPaidPartiallyReasonDiscountVat=Remaining unpaid <b>(%s %s)</b> is a discount granted because payment was made before term. I recover the VAT on this discount without a credit note. 
 ConfirmClassifyPaidPartiallyReasonBadCustomer=Bad customer
 ConfirmClassifyPaidPartiallyReasonProductReturned=Products partially returned
 ConfirmClassifyPaidPartiallyReasonOther=Amount abandoned for other reason
@@ -191,9 +191,9 @@ AlreadyPaid=Already paid
 AlreadyPaidBack=Already paid back
 AlreadyPaidNoCreditNotesNoDeposits=Already paid (without credit notes and deposits)
 Abandoned=Abandoned
-RemainderToPay=Remainder to pay
-RemainderToTake=Remainder to take
-RemainderToPayBack=Remainder to pay back
+RemainderToPay=Remaining unpaid
+RemainderToTake=Remaining amount to take
+RemainderToPayBack=Remaining amount to pay back
 Rest=Pending
 AmountExpected=Amount claimed
 ExcessReceived=Excess received
diff --git a/htdocs/langs/en_US/errors.lang b/htdocs/langs/en_US/errors.lang
index a2757bf5332..0187c567eb6 100644
--- a/htdocs/langs/en_US/errors.lang
+++ b/htdocs/langs/en_US/errors.lang
@@ -114,6 +114,7 @@ ErrorLoginDoesNotExists=User with login <b>%s</b> could not be found.
 ErrorLoginHasNoEmail=This user has no email address. Process aborted.
 ErrorBadValueForCode=Bad value for security code. Try again with new value...
 ErrorBothFieldCantBeNegative=Fields %s and %s can't be both negative
+ErrorQtyForCustomerInvoiceCantBeNegative=Quantity for line into customer invoices can't be negative
 ErrorWebServerUserHasNotPermission=User account <b>%s</b> used to execute web server has no permission for that
 ErrorNoActivatedBarcode=No barcode type activated
 ErrUnzipFails=Failed to unzip %s with ZipArchive
diff --git a/htdocs/langs/en_US/margins.lang b/htdocs/langs/en_US/margins.lang
index 3fca6d7a644..38b6482a4f3 100644
--- a/htdocs/langs/en_US/margins.lang
+++ b/htdocs/langs/en_US/margins.lang
@@ -38,4 +38,6 @@ BuyingCost=Cost price
 UnitCharges=Unit charges
 Charges=Charges
 AgentContactType=Commercial agent contact type
-AgentContactTypeDetails=Défine what contact type (linked on invoices) will be used for margin report by commercial agents
+AgentContactTypeDetails=Define what contact type (linked on invoices) will be used for margin report per sale representative
+rateMustBeNumeric=Rate must be a numeric value
+markRateShouldBeLesserThan100=Mark rate should be lower than 100