I looked at your file, but it's going to take someone with more experience to figure this out. If I use 2D selector property, all looks fine. I can get all objects on the work plane, except the lines on GIP. But if you look at the drawing from the front, that is edge on, the lines appear to be on the work plane and connected to the arcs on GIP. When I select one of the lines, it appears that the reference point is Z offset by -0.027. I tried resetting it to default, or to one of its vertices, but still seems that it has the Z offset, yet appears to be on the work plane. So I'm at a lost as to what is up with those lines. Probably something simple I am missing. Sure, I can delete those lines and redraw them on the work plane, but I don't think that is what you want to do.
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