Maybe related, it cuts off the special buttons in some editors, like launch.json:

@alexandrudima am I doing something wrong, for me I see no separation to the minimap:

This is running "out of sources".

The shadow is dropped when there is a horizontal scrollbar and the scrollLeft is not at its maximum position. Exactly how the top shadow works (the top shadow drops when there is a vertical scrollbar and the scrollLeft is not at its minimum position)

i.e. make a line long enough that it is wider than the viewport.

@alexandrudima oh I see, I somehow thought this would mean to add a general separation from the editor. E.g. I think it still looks a bit weird in this case where the viewzone just stops:

The scrollbar to the right for example has a very visible border.

Yeah, that looks slightly weird. I wonder why the tree is not in the same dark blue shade. Perhaps that would help. i.e. on the left hand side it doesn't feel weird. @jrieken

I would love a UX designer input here ...

Unsure how the color have been defined. I think someone aligned with the explorer... UX input please. Tho it might make sense to always show the drop shadow?

The dom arrangement of things doesn't make the shadow work either. I suggest we open a separate issue for the embedded editors case:

Or maybe start to draw a border if and only if a viewzone is there?

Let's track in #21359. This issue solves the problem for the text overflowing case, but not the embedded editors case.