Popup not hiding: Your To Do tasks aren't available here
The popup started showing up just recently, it's probably connected with unavaliability of To Do tasks with self-hosted Exchange.
The popup never disappears, which effectively prevents me to click anything underneath it. After clicking "Open To Do" link, it temporarely disappears, but on next application launch, it's back again.
Ondrej Novak commented
Forgot to attach a screenshot