Draw: How to protect line positions

I created a drawing and then I saved it there were no overlapping lines.
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After I saved the drawing to an .odg, I reopened the file and it had overlapping lines.
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How do I get Draw to protect line positions so that the lines remain the same after I save and reopen the file?

If you have used connectors, then it is bug https://bugs.freedesktop.org/show_bug.cgi?id=70210. It is fixed on master (towards LO 4.2). It is not clear, whether the fix will be applied to LO 4.1 too.

It took me a while but I finally got the lines to stay in place by converting them into a polygon.