Enable the ad blocker, i.e. Ghostery to "Trust Site". Reload the page and layer selection/deselection should perform smoothly.
This issue seem to be from addons or extension that are installed on the browser.
To solve this, on your browser, navigate to the where the addons/extensions are managed.
Click on the ad blocking addon/extension.
Then click "Trust Site" or disable for site.
Reload the M|511 and it should perform smoothly.