edit style in main.html to this
.topnav input{float: left; color: #f2f2f2; text-align: center; padding: 14px 16px; text-decoration: none; font-size: 17px; background-color: #333;border: none;-moz-user-select: -moz-none; -khtml-user-select: none; -webkit-user-select: none; -o-user-select: none; user-select: none;}.topnav input:hover { background-color: #ddd; color: black; -moz-user-select: -moz-none; -khtml-user-select: none; -webkit-user-select: none; -o-user-select: none; user-select: none;}.topnav input.active { background-color: #04AA6D; color: white; -moz-user-select: -moz-none; -khtml-user-select: none; -webkit-user-select: none; -o-user-select: none; user-select: none;}To disable the selection of button on top bar