Index: src/js/_enqueues/lib/embed-template.js
===================================================================
--- src/js/_enqueues/lib/embed-template.js	(revision 45550)
+++ src/js/_enqueues/lib/embed-template.js	(working copy)
@@ -161,6 +161,11 @@
 				href = target.parentElement.getAttribute( 'href' );
 			}
 
+			// Only clicks from the primary mouse button need to be catched
+			if ( e.button !== 0 ) {
+				return;
+			}
+
 			/**
 			 * Send link target to the parent (embedding) site.
 			 */