Does anyone have any idea why I get this happening?
Here are two screenshots of the same drawing, one in SU, the other how it looks in LO. The extension lines are much longer in LO. Also a part of a line showing the corner has disappeared in the LO version. I have not changed the style in LO.
In good WYSIWYG tradition, I expect what I see in SU to be replicated in LO, with LO just providing “windows” into the SU drawing. But maybe there is some global setting I need to change?