These changes look pretty good. I'd be happy to play with a local copy that includes these changes if you're looking for comfort before checking in . -- DavidOrnstein

I found a bug in the caching of the drop down list. It was using a key that had the version embeded in it. This caused multiple cache entries to exist for a given TopicName. I changed the code so it would cache by TopicName only. Once hoop checks in ShowTopicPage.cs I can make the rest of my changes in source control. -- MikeLinnen

Here is the code that needs to change in the ShowTopicPage.cs

Was

  string changesKey = "ChangesForTopic." + topic.FullnameWithVersion;

Should be

  string changesKey = "ChangesForTopic." + topic.Fullname;

Modify the 'ShowTopicPage.DoPage' method

 bool diffs = Request.QueryString["diff"] == "y";
 // Add the following code
 bool restore = Request.QueryString["restore"] == "y";
 if (restore==true)
 {
    Response.Redirect(lm.LinkToTopic(this.RestorePreviousVersion(topic)));
 }


 // Some additional code removed for clarity


 // Add an else condition to the topic.Version test
 if (topic.Version == null)
 {
    Command(lm, "Edit", lm.LinkToEditTopic(topic));
 }
 else
 {
    Command(lm, "Restore", lm.LinkToRestore(topic));
 }

Modify the LinkMaker class by adding a LinkToRestore method

 public string LinkToRestore(TopicName topic)
 {
    StringBuilder builder = new StringBuilder();
    builder.Append(SiteURL());
    builder.Append("default.aspx/");
    builder.Append(topic.FullnameWithVersion);
    string query = "";
    query += "&";
    query += "restore=y";
    builder.Append("?");
    builder.Append(query);
    return builder.ToString();
 }

Modify the Page class by adding a 'RestorePreviousVersion' method

 protected TopicName RestorePreviousVersion(TopicName topic)
 {
    AbsoluteTopicName newVersionName = new AbsoluteTopicName(topic.Name, topic.Namespace);
    newVersionName.Version = TopicName.NewVersionStringForUser(VisitorIdentityString);
    DefaultContentBase.WriteTopicAndNewVersion(newVersionName, this.DefaultContentBase.Read(topic));
    return this.DefaultContentBase.TopicNameFor(newVersionName.Name);
 }

This enhancement is complete and checked into source control -- Mike Linnen