diff --git a/include/lib/pdf_core.class.php b/include/lib/pdf_core.class.php
index d46355f3c..3b4563889 100644
--- a/include/lib/pdf_core.class.php
+++ b/include/lib/pdf_core.class.php
@@ -264,7 +264,7 @@ class PDF_Core extends TFPDF
             $this->bigger=0;
     }
     /**
-     * If the step is even then return 1 and set the backgroup color to blue , otherwise
+     * @brief If the step is even then return 1 and set the backgroup color to blue , otherwise
      * returns 0, and set the background color to white
      * It is use to compute alternated  colored row , it the parameter fill in write_cell and 
      * cell
@@ -281,7 +281,7 @@ class PDF_Core extends TFPDF
             $this->SetFillColor(255, 255, 255);
             $fill = 0;
         }
-        return $p_step;
+        return $fill;
     }
 
 
diff --git a/include/template/stock_histo.php b/include/template/stock_histo.php
index bdb496de5..2c61a5a10 100644
--- a/include/template/stock_histo.php
+++ b/include/template/stock_histo.php
@@ -59,12 +59,12 @@
 			<?php echo $row['r_name']?>
 		</td>
 		<td>
-			<?php if (trim($row['qcode'])!='') : ?>
+			<?php if (trim($row['qcode']??"")!='') : ?>
 			<?php echo HtmlInput::card_detail($row['qcode'],$row['fname'],' class="line" ')?>
 			<?php endif; ?>
 		</td>
 		<td>
-			<?php if (trim($row['jr_internal'])!='') : ?>
+			<?php if (trim($row['jr_internal']??"")!='') : ?>
 			<?php echo HtmlInput::detail_op($row['jr_id'],$row['jr_internal'])?>
 			<?php endif; ?>
 		</td>
diff --git a/include/template/stock_summary_table.php b/include/template/stock_summary_table.php
index 485bd74dc..a191be1da 100644
--- a/include/template/stock_summary_table.php
+++ b/include/template/stock_summary_table.php
@@ -89,7 +89,7 @@
 									<?php echo _("DIFF")?>  :
 								</td>
 								<td class="num">
-									<?php echo nbm((bcsub($array[0]['s_qin'],$array[0]['s_qout'])))?>
+									<?php echo nbm((bcsub($array[0]['s_qin']??0,$array[0]['s_qout']??0)))?>
 								</td>
 							</tr>
 						</table>