Hi Eric,

I can confirm that the functionality is working as expected, and the z-index style is correctly incremented each time a Window gains focus. However, there is indeed an issue, but it is due to the demo example itself. To be more specific, the z-index of each Window is overridden by a `.demo-window` selector. Now that you have brought this to our attention, we will update the demo, so the custom styling of the demo does not interfere with the demonstrated functionality - thank you for bringing it up.

I have also prepared an example, where the above-mentioned selector is removed, and the functionality can be tested: https://blazorrepl.telerik.com/QROvcUui47Ffzscp56

Regards, Radko Stanev Progress Telerik