When using the <Window> component, there is an issue trying to maximize, when a parent element has positioning (ie: position: absolute, position: relative). The calculation for defining the width uses window.innerWidth (similar for height). However, for placement, it uses top and left = 0.
You can see a sample of this on StackBlitz:
This is a straight copy of https://www.telerik.com/kendo-react-ui/components/dialogs/window/controlled-mode/, but added the additional styles to the parent <div>.
Version is 3.14.