diff --git a/src/calibre/gui2/comments_editor.py b/src/calibre/gui2/comments_editor.py
index 451ae4414f..1bd3d3137e 100644
--- a/src/calibre/gui2/comments_editor.py
+++ b/src/calibre/gui2/comments_editor.py
@@ -83,7 +83,7 @@ def filter_qt_styles(style):
 
 def remove_margins(tag, style):
     ml, mr, mt, mb = (style.pop('margin-' + k, None) for k in 'left right top bottom'.split())
-    is_blockquote = ml == mr and ml and ml != '0px'
+    is_blockquote = ml == mr and ml and ml != '0px' and (ml != mt or ml != mb)
     if is_blockquote:
         tag.tag = 'blockquote'