When i try to use window i end up with a bunch of errors. Window appears but they are not draggable, or take the fullviewport, or crash when you click the close button…, with the example you provide i just succeed to make it appear in the middle and i can’t close them or move them. I have to close the editor to make them disappear.
I would prefer to use SWindow rather than Soverlay or Scanvas but i can’t make them work.
Is it working for you with just that code ?