Hi all.
Just trying to change label in "Root.Content.Main.Title"

class DepartmentPage extends Page {
   function getCMSFields() {
      $fields = parent::getCMSFields();
      
      $gg = $fields->fieldByName("Root.Content.Main.Title"); // same error with filedByName("Title").
      $gg->setTitle("My new Title");

I get this error
Fatal error: Call to a member function setTitle() on a non-object in /public_html/silverstripe/tutorial/code/DepartmentPage.php on line 27

Thanks in advanced.

got the answer.

use dataFieldByName("Title")instead fieldByName("Title").

That leads me to a question?

What does fieldByName() retrieve?.

Thanks.

fieldByName() returns a field at the top level.

dataFieldByName() checks in tabs as well.