Q:

Visualforce page to create a new Opp Contact Role

Is it possible to create a custom Visualforce page for adding a new Opportunity Contact Role using standard controllers (Opportunity controller in this case)? 
The reason I'm asking is that I'd like to avoid writing any code for a custom controller. 
The objective for the custom VF page is to make "isPrimary" field required when adding a new Opp Contact Role, which is not something that comes out of the box in Lightning Salesforce (different from classic). 
Many thanks in advance

A:

You can create a page for this, but there's no way to override the New Contact Role page.  So, you'd have to hide the Contact Role Related List and build everything custom, such as adding a custom button for viewing/adding/removing roles.  This is probably a lot more work than you'd bargained for.  You may as well write this off as a training issue.