No continuous line although defined in layer

Hi everyone,

I just recently downloaded LibreCAD to make some simple scaled figures for my master thesis. So I'm pretty new to it and I might miss just a simple thing.

The problem:
The layers I'm working with are all set to have continuous line types but in most cases they are not. I just had one layer defined with line type "dash (tiny)" but changed it back to continous after. And I think (but am not shure) that after this most of the lines are dashed although defined as continuous. First I wasn't sure but after I saved the file as a PDF the lines are clearly not continuous.
All the lines I drew are defined by the layers setting and not changed individually, so its not this problem. However, when I zoom in the lines get continuous but when I'm on the scale to see the whole figure the lines are dashed/dotted.
Uploaded is a srceenshot of the created PDF.



The system I'm working on is Windows 8.1 64-bit
LibreCAD version 5.4.0

hopefully someone can help me.

Kind Regards,
Al