diff --git a/src/calibre/gui2/tweak_book/diff/main.py b/src/calibre/gui2/tweak_book/diff/main.py
index ba95ca6110..2a0a6072a9 100644
--- a/src/calibre/gui2/tweak_book/diff/main.py
+++ b/src/calibre/gui2/tweak_book/diff/main.py
@@ -82,7 +82,7 @@ def changed_files(list_of_names1, list_of_names2, get_data1, get_data2):
                 adds.discard(n)
                 break
         else:
-            cache.set_left(name, adata[name])
+            cache.set_left(name, rdata[name])
             removed_names.add(name)
     for name in adds:
         cache.set_right(name, adata[name])
@@ -217,12 +217,12 @@ class Diff(Dialog):
             add(args, kwargs)
 
         for name in sorted(added_names, key=numeric_sort_key):
-            args = (_('[This file was added]'), name, None, cache.right(name))
+            args = (_('[%s was added]') % name, name, None, cache.right(name))
             kwargs = {'syntax':syntax_map.get(name, None), 'context':self.context}
             add(args, kwargs)
 
         for name in sorted(removed_names, key=numeric_sort_key):
-            args = (name, _('[This file was removed]'), cache.left(name), None)
+            args = (name, _('[%s was removed]') % name, cache.left(name), None)
             kwargs = {'syntax':syntax_map.get(name, None), 'context':self.context}
             add(args, kwargs)
 
diff --git a/src/calibre/gui2/tweak_book/diff/view.py b/src/calibre/gui2/tweak_book/diff/view.py
index 965d8ab2ff..1cd50b5163 100644
--- a/src/calibre/gui2/tweak_book/diff/view.py
+++ b/src/calibre/gui2/tweak_book/diff/view.py
@@ -461,7 +461,7 @@ class DiffSplit(QSplitter):  # {{{
                     c.movePosition(c.End)
                     c.insertText('[%s]\n\n' % _('The files are identical'))
             elif left_name != right_name and not left_text and not right_text:
-                self.add_text_diff(_('[This file was renamed to %s]') % right_name, _('[This file was renamed from %s]') % left_name, context, syntax)
+                self.add_text_diff(_('[This file was renamed to %s]') % right_name, _('[This file was renamed from %s]') % left_name, context, None)
                 for v in (self.left, self.right):
                     v.appendPlainText('\n')
             elif is_text:
@@ -872,10 +872,11 @@ class DiffView(QWidget):  # {{{
         self.syncing = False
 
     def clear(self):
-        self.view.clear()
-        self.changes = []
-        self.delta = 0
-        self.scrollbar.setRange(0, 0)
+        with self:
+            self.view.clear()
+            self.changes = []
+            self.delta = 0
+            self.scrollbar.setRange(0, 0)
 
     def adjust_range(self):
         ls, rs = self.view.left.verticalScrollBar(), self.view.right.verticalScrollBar()