diff --git a/htdocs/core/class/commonobject.class.php b/htdocs/core/class/commonobject.class.php
index d1cee09dbcc..9320daefd0a 100644
--- a/htdocs/core/class/commonobject.class.php
+++ b/htdocs/core/class/commonobject.class.php
@@ -2352,7 +2352,13 @@ abstract class CommonObject
             global $linkedObjectBlock;
             $linkedObjectBlock = $objects;
 
-            dol_include_once('/'.$tplpath.'/tpl/linkedobjectblock.tpl.php');
+            // Output template part (modules that overwrite templates must declare this into descriptor)
+            $dirtpls=array_merge($conf->modules_parts['tpl'],array('/'.$tplpath.'/tpl'));
+            foreach($dirtpls as $reldir)
+            {
+                $res=@include(dol_buildpath($reldir.'/linkedobjectblock.tpl.php'));
+                if ($res) break;
+            }
         }
 
         return $num;
@@ -2378,14 +2384,13 @@ abstract class CommonObject
 		global $conf,$langs,$object;
 		global $form,$bcnd,$var;
 
+		// Output template part (modules that overwrite templates must declare this into descriptor)
         // Use global variables + $dateSelector + $seller and $buyer
-		if (file_exists(DOL_DOCUMENT_ROOT."/theme/".$conf->theme."/tpl/predefinedproductline_create.tpl.php"))
+		$dirtpls=array_merge($conf->modules_parts['tpl'],array('/core/tpl'));
+		foreach($dirtpls as $reldir)
 		{
-			include(DOL_DOCUMENT_ROOT."/theme/".$conf->theme."/tpl/predefinedproductline_create.tpl.php");
-		}
-		else
-		{
-			include(DOL_DOCUMENT_ROOT.'/core/tpl/predefinedproductline_create.tpl.php');
+		    $res=@include(dol_buildpath($reldir.'/predefinedproductline_create.tpl.php'));
+		    if ($res) break;
 		}
     }
 
@@ -2405,14 +2410,13 @@ abstract class CommonObject
 		global $conf,$langs,$object;
 		global $form,$bcnd,$var;
 
+		// Output template part (modules that overwrite templates must declare this into descriptor)
         // Use global variables + $dateSelector + $seller and $buyer
-		if (file_exists(DOL_DOCUMENT_ROOT."/theme/".$conf->theme."/tpl/freeproductline_create.tpl.php"))
+		$dirtpls=array_merge($conf->modules_parts['tpl'],array('/core/tpl'));
+		foreach($dirtpls as $reldir)
 		{
-			include(DOL_DOCUMENT_ROOT."/theme/".$conf->theme."/tpl/freeproductline_create.tpl.php");
-		}
-		else
-		{
-			include(DOL_DOCUMENT_ROOT.'/core/tpl/freeproductline_create.tpl.php');
+		    $res=@include(dol_buildpath($reldir.'/freeproductline_create.tpl.php'));
+		    if ($res) break;
 		}
     }
 
@@ -2551,27 +2555,25 @@ abstract class CommonObject
 				$text.= ' - '.$label;
 				$description=($conf->global->PRODUIT_DESC_IN_FORM?'':dol_htmlentitiesbr($line->description));
 
-				// Use global variables + $seller and $buyer
-				if (file_exists(DOL_DOCUMENT_ROOT."/theme/".$conf->theme."/tpl/predefinedproductline_view.tpl.php"))
-				{
-					include(DOL_DOCUMENT_ROOT."/theme/".$conf->theme."/tpl/predefinedproductline_view.tpl.php");
-				}
-				else
-				{
-					include(DOL_DOCUMENT_ROOT.'/core/tpl/predefinedproductline_view.tpl.php');
-				}
+				// Output template part (modules that overwrite templates must declare this into descriptor)
+                // Use global variables + $dateSelector + $seller and $buyer
+        		$dirtpls=array_merge($conf->modules_parts['tpl'],array('/core/tpl'));
+        		foreach($dirtpls as $reldir)
+        		{
+        		    $res=@include(dol_buildpath($reldir.'/predefinedproductline_view.tpl.php'));
+        		    if ($res) break;
+        		}
 			}
 			else
 			{
-				// Use global variables + $dateSelector + $seller and $buyer
-				if (file_exists(DOL_DOCUMENT_ROOT."/theme/".$conf->theme."/tpl/freeproductline_view.tpl.php"))
-				{
-					include(DOL_DOCUMENT_ROOT."/theme/".$conf->theme."/tpl/freeproductline_view.tpl.php");
-				}
-				else
-				{
-					include(DOL_DOCUMENT_ROOT.'/core/tpl/freeproductline_view.tpl.php');
-				}
+				// Output template part (modules that overwrite templates must declare this into descriptor)
+                // Use global variables + $dateSelector + $seller and $buyer
+        		$dirtpls=array_merge($conf->modules_parts['tpl'],array('/core/tpl'));
+        		foreach($dirtpls as $reldir)
+        		{
+        		    $res=@include(dol_buildpath($reldir.'/freeproductline_view.tpl.php'));
+        		    if ($res) break;
+        		}
 			}
 		}
 
@@ -2580,27 +2582,25 @@ abstract class CommonObject
 		{
 			if ($line->fk_product > 0)
 			{
-				// Use global variables + $dateSelector + $seller and $buyer
-				if (file_exists(DOL_DOCUMENT_ROOT."/theme/".$conf->theme."/tpl/predefinedproductline_edit.tpl.php"))
-				{
-					include(DOL_DOCUMENT_ROOT."/theme/".$conf->theme."/tpl/predefinedproductline_edit.tpl.php");
-				}
-				else
-				{
-					include(DOL_DOCUMENT_ROOT.'/core/tpl/predefinedproductline_edit.tpl.php');
-				}
+				// Output template part (modules that overwrite templates must declare this into descriptor)
+                // Use global variables + $dateSelector + $seller and $buyer
+        		$dirtpls=array_merge($conf->modules_parts['tpl'],array('/core/tpl'));
+        		foreach($dirtpls as $reldir)
+        		{
+        		    $res=@include(dol_buildpath($reldir.'/predefinedproductline_edit.tpl.php'));
+        		    if ($res) break;
+        		}
 			}
 			else
 			{
-				// Use global variables + $dateSelector + $seller and $buyer
-				if (file_exists(DOL_DOCUMENT_ROOT."/theme/".$conf->theme."/tpl/freeproductline_edit.tpl.php"))
-				{
-					include(DOL_DOCUMENT_ROOT."/theme/".$conf->theme."/tpl/freeproductline_edit.tpl.php");
-				}
-				else
-				{
-					include(DOL_DOCUMENT_ROOT.'/core/tpl/freeproductline_edit.tpl.php');
-				}
+				// Output template part (modules that overwrite templates must declare this into descriptor)
+                // Use global variables + $dateSelector + $seller and $buyer
+        		$dirtpls=array_merge($conf->modules_parts['tpl'],array('/core/tpl'));
+        		foreach($dirtpls as $reldir)
+        		{
+        		    $res=@include(dol_buildpath($reldir.'/freeproductline_edit.tpl.php'));
+        		    if ($res) break;
+        		}
 			}
 		}
 	}
@@ -2739,15 +2739,15 @@ abstract class CommonObject
         $this->tpl['price'] = price($line->subprice);
         $this->tpl['qty'] = (($line->info_bits & 2) != 2) ? $line->qty : ' ';
         $this->tpl['remise_percent'] = (($line->info_bits & 2) != 2) ? vatrate($line->remise_percent, true) : ' ';
-		
-		if (file_exists(DOL_DOCUMENT_ROOT."/theme/".$conf->theme."/tpl/originproductline.tpl.php"))
-				{
-					include(DOL_DOCUMENT_ROOT."/theme/".$conf->theme."/tpl/originproductline.tpl.php");
-				}
-				else
-				{
-					include(DOL_DOCUMENT_ROOT.'/core/tpl/originproductline.tpl.php');
-				}
+
+        // Output template part (modules that overwrite templates must declare this into descriptor)
+        // Use global variables + $dateSelector + $seller and $buyer
+        $dirtpls=array_merge($conf->modules_parts['tpl'],array('/core/tpl'));
+        foreach($dirtpls as $reldir)
+        {
+            $res=@include(dol_buildpath($reldir.'/originproductline.tpl.php'));
+            if ($res) break;
+        }
     }
 }