At 1366 px wide you should not be able to see the mobile menu drop-down box. That is working correctly on my system, using your screen dimensions and the webtrees theme that you use, displaying your site.
So what sort of laptop is that, what operating system, and what browser?
Have you ensured the browser cache has been cleared?
Is your browser window at full screen is or only partial. If only partial it is the browser window dimensions you need to know, not the total screen.