Why have topic filters suddenly disappeared from published HTML5 maps?

Until 2 days ago my published Mindmanager 2018 map when opened using a browser allowed me to filter and dim topics by icon or tag. This was really good. This was achieved by right or left clicking (I can't recall which) the icon or tag. Suddenly this feature has gone and instead the same action opens the right hand notes window which is accessible from the notes icon anyway.