In Inkscape, when I stretch a line having an end marker (e.g., an arrowhead), the marker scales. I'm not sure why anyone would want this. Is there a way to keep the same marker, and only stretch the line? I think we could assume that's what the user always wants, since for example, having different sized arrowheads in a diagram is unconventional, not to mention that it looks like kindergarten art.
The following option in the tool controls:
enables stroke width and arrowhead scaling when transforming a path.
If set, then the stroke width and arrowheads will scale together with the path. If unset, both will be unmodified when scaling.