Go to the template.
Select Work on this Page or Work on this Page (All Changes); scroll as needed to see the element that should be revised only from within the template; in class this will be the text block that you created in the top row.
For each element that should be revised only from within the template, click on the "Element Properties" icon, , which is located to the left, just above the element.
From the displayed menu, click on "more" and then choose the option "Element Inheritance Security..."
From the dialog box, click on the "Change" button in the "Restrictions" section.
In order to fully preserve inheritance, lock all the access rights to the element by checking all the check boxes ("Author/Edit," "Design," "Style," and "Admin").
Click on the "Save" button.
Click on the "Close" button.
No yellow work-in-progress icon appears: the changes made take effect immediately, and are not recorded in the Version History for this template.
From now on, while you are working on any page or derived template that was created from this template, you will notice that the element does not display the "Element Properties" icon, . The pagemaster or content contributor is therefore not able to edit or change the element while working on the page or derived template, preserving inheritance.