top 391.5 px
left 480 px
are the coordinates for the dialog box according to Chrome Inspect (dev tools)
If one interacts with the ethergroups GUI using a lower resolution, the dialog box is below the lower display edge and therefore not visible to the end-user. One has to scroll down the greyed-out page to see the dialog box. You may want to change the coordinates from absolute pixels to relative per cent location pointers.
Thank you for your efforts.