thanks, but I knew that, my problem is that some lines on defpoints were still plotted, while I didn't want them to.
Finally i threw the old lines away and drew them again. that worked fine. Still curious what went wrong earlier.
That is weird. Were they blocks, construction lines, 3D lines, LWPolylines, in Model or Paper space? Anything odd or unusual about them? What version of AutoCAD are you using?