diff --git a/lib/redmine/unified_diff.rb b/lib/redmine/unified_diff.rb
index 3aa348f41..84c376764 100644
--- a/lib/redmine/unified_diff.rb
+++ b/lib/redmine/unified_diff.rb
@@ -112,11 +112,6 @@ module Redmine
 
     private
 
-    # Escape the HTML for the diff
-    def escapeHTML(line)
-        CGI.escapeHTML(line)
-    end
-
     def diff_for_added_line
       if @type == 'sbs' && @removed > 0 && @added < @removed
         self[-(@removed - @added)]
@@ -130,7 +125,7 @@ module Redmine
     def parse_line(line, type="inline")
       if line[0, 1] == "+"
         diff = diff_for_added_line
-        diff.line_right = escapeHTML line[1..-1]
+        diff.line_right = line[1..-1]
         diff.nb_line_right = @line_num_r
         diff.type_diff_right = 'diff_in'
         @line_num_r += 1
@@ -138,7 +133,7 @@ module Redmine
         true
       elsif line[0, 1] == "-"
         diff = Diff.new
-        diff.line_left = escapeHTML line[1..-1]
+        diff.line_left = line[1..-1]
         diff.nb_line_left = @line_num_l
         diff.type_diff_left = 'diff_out'
         self << diff
@@ -149,9 +144,9 @@ module Redmine
         write_offsets
         if line[0, 1] =~ /\s/
           diff = Diff.new
-          diff.line_right = escapeHTML line[1..-1]
+          diff.line_right = line[1..-1]
           diff.nb_line_right = @line_num_r
-          diff.line_left = escapeHTML line[1..-1]
+          diff.line_left = line[1..-1]
           diff.nb_line_left = @line_num_l
           self << diff
           @line_num_l += 1
@@ -224,27 +219,15 @@ module Redmine
     end
 
     def html_line_left
-      if offsets
-        line_left.dup.insert(offsets.first, '<span>').insert(offsets.last, '</span>')
-      else
-        line_left
-      end
+      line_to_html(line_left, offsets)
     end
 
     def html_line_right
-      if offsets
-        line_right.dup.insert(offsets.first, '<span>').insert(offsets.last, '</span>')
-      else
-        line_right
-      end
+      line_to_html(line_right, offsets)
     end
 
     def html_line
-      if offsets
-        line.dup.insert(offsets.first, '<span>').insert(offsets.last, '</span>')
-      else
-        line
-      end
+      line_to_html(line, offsets)
     end
 
     def inspect
@@ -254,5 +237,23 @@ module Redmine
       puts self.nb_line_right
       puts self.line_right
     end
+
+    private
+
+    def line_to_html(line, offsets)
+      if offsets
+        s = ''
+        unless offsets.first == 0
+          s << CGI.escapeHTML(line[0..offsets.first-1])
+        end
+        s << '<span>' + CGI.escapeHTML(line[offsets.first..offsets.last]) + '</span>'
+        unless offsets.last == -1
+          s << CGI.escapeHTML(line[offsets.last+1..-1])
+        end
+        s
+      else
+        CGI.escapeHTML(line)
+      end
+    end
   end
 end
diff --git a/test/unit/lib/redmine/unified_diff_test.rb b/test/unit/lib/redmine/unified_diff_test.rb
index 8d3e70497..01b899a02 100644
--- a/test/unit/lib/redmine/unified_diff_test.rb
+++ b/test/unit/lib/redmine/unified_diff_test.rb
@@ -91,6 +91,29 @@ class Redmine::UnifiedDiffTest < ActiveSupport::TestCase
 
   end
 
+  def test_partials_with_html_entities
+    raw = <<-DIFF
+--- test.orig.txt Wed Feb 15 16:10:39 2012
++++ test.new.txt  Wed Feb 15 16:11:25 2012
+@@ -1,5 +1,5 @@
+ Semicolons were mysteriously appearing in code diffs in the repository
+ 
+-void DoSomething(std::auto_ptr<MyClass> myObj)
++void DoSomething(const MyClass& myObj)
+ 
+DIFF
+
+    diff = Redmine::UnifiedDiff.new(raw, :type => 'sbs')
+    assert_equal 1, diff.size
+    assert_equal 'void DoSomething(<span>std::auto_ptr&lt;MyClass&gt;</span> myObj)', diff.first[2].html_line_left
+    assert_equal 'void DoSomething(<span>const MyClass&amp;</span> myObj)', diff.first[2].html_line_right
+
+    diff = Redmine::UnifiedDiff.new(raw, :type => 'inline')
+    assert_equal 1, diff.size
+    assert_equal 'void DoSomething(<span>std::auto_ptr&lt;MyClass&gt;</span> myObj)', diff.first[2].html_line
+    assert_equal 'void DoSomething(<span>const MyClass&amp;</span> myObj)', diff.first[3].html_line
+  end
+
   def test_line_starting_with_dashes
     diff = Redmine::UnifiedDiff.new(<<-DIFF
 --- old.txt Wed Nov 11 14:24:58 2009