Everything wrong with the software of my Librem 5

It is possible using Emacs(Terminal)
at least that is tha way I do it

As user0 explained it’s just a matter of CSS-configs. The idea behind “putting extensions into overflow window” is to use a modifiable container that works for all extensions without exceptions and to modify this container via CSS-config. Sadly it doesn’t work out of the box, but we already found a solution as you can see.