formatting – draw.io: How to remove the tiny white space between two lines

If you were to align two straight lines, one on top of the other, such as this:

enter image description here

A tiny white space exists between them. Is there any good way to remove such an artifact? Obviously in this case above I could simply draw a longer line, but the diagrams I am drawing are more complicated so I was hoping for a more general answer. I also cannot simply move the bottom line slightly upwards, as often my top line is curved, leading to situations such as this:

enter image description here