diff --git a/include/class.forms.php b/include/class.forms.php
index 0fc575637fb65985892316196c8697f55e15211e..0e973557752910e08fef1ce710dbf1d4d01c877a 100644
--- a/include/class.forms.php
+++ b/include/class.forms.php
@@ -3974,7 +3974,10 @@ class FileUploadWidget extends Widget {
         // Files already attached to the field are allowed
         foreach ($this->field->getFiles() as $F) {
             // FIXME: This will need special porting in v1.10
-            $allowed[$F->id] = 1;
+            if ($F instanceof Attachment)
+                $allowed[$F->getFileId()] = 1;
+            else
+                $allowed[$F->id] = 1;
         }
 
         // New files uploaded in this session are allowed