Apostrophe's that display in Title show up as '

Created a piece of content and want to clone it. When I select 'Clone content', and the title of the node page is 'Clone of This is the test for apostrophe's - lets see.', the Title that displays at the top of the page contains apostrophe's

I've attached an image (apostrophe.png) to see the actual Title that is displayed.

This is a minor issue as the title is being saved correctly and only the displayed title contains apostrophe's. Looked into the code and found the possible reason for this problem..

function clone_node_prepopulate($original_node) {

"
"
 $node->title = t('Clone of !title', array('!title' => $node->title));
      // Add an extra property as a flag.
      $node->clone_from_original_nid = $original_node->nid;
      drupal_set_title(check_plain($node->title));

}

The code is using drupal_set_title and also using check_plain. check_plain is not needed as drupal_set_title also uses check_plain. I've tested the following code and it works correctly..

function clone_node_prepopulate($original_node) {

"
"
 $node->title = t('Clone of !title', array('!title' => $node->title));
      // Add an extra property as a flag.
      $node->clone_from_original_nid = $original_node->nid;
      drupal_set_title($node->title);

}