Most visited Thumbnail won't delete on NewTab

As the title said. After deleting a thumbnail in New Tab windows, those deleted ones reapears after refreshing the page. Also clicking “Undo” or “Restore all” does nothing.
Comodo 80…163, 64bits, on Windows 7.

Hello yomaus , thank you for taking your time to report this issue, if you do not mind you can re-install the browser i think it might be an error of some sort during installation, usually the undo button should restore the last website deleted and restore all will restore all deleted, normally you just have to press x to delete it nothing and nothing alse…