Overview of viewport when viewport is selected

It would be nice, when using a scale f.e 1:1 or 1:5 e.t.c that when we have selected a viewport that we can see what is the visible part of the viewport of the whole drawing linked to that viewport in a separated dialog. Aka photoshop where we can see a rectangle of the drawing versus the whole canvas.

Of course, also that we can move the rectangle on that dialog and that the object in the viewport moves likewise.

Hmm Question - is this possible with Ruby?

Also, like mentioned in other requests, please when we change a scale setting, don’t let the object jump around.