ELECTRON-591 - Add logic to close up child windows whenever parent window is navigated or reloaded (#446)

js/mainApiMgr.js

@@ -67,6 +67,8 @@ function sanitize(windowName) {
         if (!isMac) {
             eventEmitter.emit('killScreenSnippet');
         }
+        // Closes all the child windows
+        windowMgr.cleanUpChildWindows();
     }
 }