SPPB 4.06 , php8.0 , any template, Firefox/Edge

I want to add an image into a block , or background of a row

Steps:

open the "Row Options" (little gear wheel)
Media-Manager opens
select style/image
replace or clear Image
it opens the list of images
scroll down to the end of the list
when you reach the end of the list, the spinner appears
as soon as you focus the spinner

the windows closes
on the edit-page you can not open the "Options" of any block / row
you only can hide, delete, insert new block
no way back to admin-Window

Here you find a screen record: https://hidrive.ionos.com/share/64opk2ib4l