Shadow and Feathering Weirdness. Stretching horizontal and vertical is different.

[Acorn]

indeed.. but I don't think the shadow tool is indended for illustration/artisitic work, it is more a shortcut for creating emphasis on graphics in a similar way to putting an outline on a box

My workaround it to keep a Shadow Group copy of a Line off page and use Ctrl+C > Ctrl+Shift+A as sadly the Shape Fill attribute copies over as well as the Shadow ones.

With a Line, it is quicker to remove or change the Line Width.
It is possible to do this with a Line of None Line Width but both it and the Shadow become invisible bit they are still functional, if you can find them.

Acorn