Can I arrange all the nodes on the selected path horizontally as possible?

[6br]

Hello, I would like to arrange all the nodes on the selected path horizontally. I also hope to align all the paths horizontally as possible.

I am trying to do so in this branch, but it fails in some cases.

In this case, the blue path is selected and it is able to align horizontally at all. But, the green path is overlapping with the blue path. Moreover, the purple path can be more straightened.

I would be grateful if you could check it.