When filter popup is opened, it need to be closed by click outside of it
However, popup is closed only after second click outside.
After popup was opened and closed for the first time - next times everything works correctly, so it can be reproduced only after refreshing the page with this component
It can be reproduced in example in your documentation: https://www.telerik.com/kendo-angular-ui/components/grid/filtering/filter-menu/#toc-custom-filters/