While "zoomed-in" to a specific day, the Add Task button is highlighted on mouse-over but clicking does nothing.
It has been fixed during 11.10.2017 deployment.
Thank you for reporting that problem and please check if everything is fine now.
Thank you for reaching out and letting us know about this. We will have the Technical team check and we will get back t you as soon as we have an update.
Customer support service by UserEcho