diff --git a/htdocs/compta/facture/mergepdftool.php b/htdocs/compta/facture/mergepdftool.php
index 146ee53736c..e8010229a8e 100644
--- a/htdocs/compta/facture/mergepdftool.php
+++ b/htdocs/compta/facture/mergepdftool.php
@@ -810,10 +810,8 @@ if ($resql)
 			{
 				// Checkbox to merge
 				print '<td align="center">';
-				if (! empty($formfile->numoffiles))
+				if (! empty($formfile->infofiles['extensions']['pdf']))
 					print '<input id="cb'.$objp->facid.'" class="flat checkformerge" type="checkbox" name="toGenerate[]" value="'.$objp->facnumber.'">';
-				else
-					print '&nbsp;';
 				print '</td>' ;
 			}
 			else
diff --git a/htdocs/core/class/html.formfile.class.php b/htdocs/core/class/html.formfile.class.php
index aab33fa56d2..d273eef1462 100644
--- a/htdocs/core/class/html.formfile.class.php
+++ b/htdocs/core/class/html.formfile.class.php
@@ -37,6 +37,7 @@ class FormFile
     var $error;
 
     var $numoffiles;
+	var $infofiles;			// Used to return informations by function getDocumentsLink
 
 
     /**
@@ -680,16 +681,17 @@ class FormFile
      *	@param	string	$modulepart		propal, facture, facture_fourn, ...
      *	@param	string	$modulesubdir	Sub-directory to scan (Example: '0/1/10', 'FA/DD/MM/YY/9999'). Use '' if file is not into subdir of module.
      *	@param	string	$filedir		Directory to scan
-     *	@return	string              	Output string with HTML link of documents (might be empty string)
+     *  @param	string	$filter			Filter filenames on this regex string (Example: '\.pdf$')
+     *	@return	string              	Output string with HTML link of documents (might be empty string). This also fill the array ->infofiles
      */
-    function getDocumentsLink($modulepart, $modulesubdir, $filedir)
+    function getDocumentsLink($modulepart, $modulesubdir, $filedir, $filter='')
     {
-    	if (! function_exists('dol_dir_list')) include_once DOL_DOCUMENT_ROOT.'/core/lib/files.lib.php';
+    	include_once DOL_DOCUMENT_ROOT.'/core/lib/files.lib.php';
 
     	$out='';
-    	$this->numoffiles=0;
+    	$this->infofiles=array('nboffiles'=>0,'extensions'=>array(),'files'=>array());
 
-		$file_list=dol_dir_list($filedir, 'files', 0, preg_quote(basename($modulesubdir),'/').'[^\-]+', '\.meta$|\.png$');
+		$file_list=dol_dir_list($filedir, 'files', 0, preg_quote(basename($modulesubdir),'/').'[^\-]+', '\.meta$|\.png$');	// Get list of files starting with name fo ref (but not followed by "-" to discard uploaded files)
 
     	// For ajax treatment
     	$out.= '<div id="gen_pdf_'.$modulesubdir.'" class="linkobject hideobject">'.img_picto('', 'refresh').'</div>'."\n";
@@ -699,6 +701,8 @@ class FormFile
     		// Loop on each file found
     		foreach($file_list as $file)
     		{
+    			if ($filter && ! preg_match('/'.$filter.'/i', $file["name"])) continue;	// Discard this. It does not match provided filter.
+
     			// Define relative path for download link (depends on module)
     			$relativepath=$file["name"];								// Cas general
     			if ($modulesubdir) $relativepath=$modulesubdir."/".$file["name"];	// Cas propal, facture...
@@ -721,7 +725,11 @@ class FormFile
     			$out.= img_mime($relativepath, $file["name"]);
     			$out.= '</a>'."\n";
 
-    			$this->numoffiles++;
+    			$this->infofiles['nboffiles']++;
+    			$this->infofiles['files'][]=$file['fullname'];
+    			$ext=pathinfo($file["name"], PATHINFO_EXTENSION);
+    			if (empty($this->infofiles[$ext])) $this->infofiles['extensions'][$ext]=1;
+    			else $this->infofiles['extensions'][$ext]++;
     		}
     	}