Editing room with diagonal wall

I'm trying to expand a fence by expanding the room on one side, but the whole thing moves and I'm not able to expand to the border of the property and to be flush, attached image is what I was trying to do.

But I have to delete the fences and do the whole thing again. ;_;

It could make building feel more free flowing if there's a button to switch from dragging with the diagonal to dragging it to be flush, or diagonal past that to automatically.

Hope this idea is worthy 🙏 🙌 ❤️