diff --git a/resources/compiled_coffeescript.zip b/resources/compiled_coffeescript.zip
index c6e68ec1fe..65c3b78952 100644
Binary files a/resources/compiled_coffeescript.zip and b/resources/compiled_coffeescript.zip differ
diff --git a/src/calibre/ebooks/oeb/polish/preview.coffee b/src/calibre/ebooks/oeb/polish/preview.coffee
index e140177373..8792ae891a 100644
--- a/src/calibre/ebooks/oeb/polish/preview.coffee
+++ b/src/calibre/ebooks/oeb/polish/preview.coffee
@@ -336,7 +336,7 @@ class PreviewIntegration
         while target and target.ownerDocument
             css = get_matched_css(target, is_ancestor, all_properties)
             if css.length > 0
-                ans['nodes'].push({'name':target.tagName?.toLowerCase(), 'css':css, 'is_ancestor':is_ancestor})
+                ans['nodes'].push({'name':target.tagName?.toLowerCase(), 'css':css, 'is_ancestor':is_ancestor, 'sourceline':target.getAttribute('data-lnum')})
             target = target.parentNode
             is_ancestor = true
         return JSON.stringify(ans)
diff --git a/src/calibre/gui2/tweak_book/live_css.py b/src/calibre/gui2/tweak_book/live_css.py
index 07f72e0747..08eadd045c 100644
--- a/src/calibre/gui2/tweak_book/live_css.py
+++ b/src/calibre/gui2/tweak_book/live_css.py
@@ -227,7 +227,7 @@ class Box(QWidget):
             w.deleteLater()
         self.widgets = []
         for node in data['nodes']:
-            node_name = node['name']
+            node_name = node['name'] + ' @%s' % node['sourceline']
             if node['is_ancestor']:
                 title = _('Inherited from %s') % node_name
             else: