Fix return to be consistent fixing eslint

Author: wilsonge

src/js/tab/tab.js

@@ -388,7 +388,7 @@
       while (element.nodeName.toLowerCase() !== tagName) {
         // Ensure we haven't reached the top of the dom tree
         if (element.parentElement === null) {
-          return;
+          return false;
         }
         element = element.parentElement;
       }