2-point line draws line with infinite extention

Hi,

I am new to libreCAD vsn 2.1.3 and still figuring it out but I think I have inadvertently set a mode or switch. In my drawing I have a couple of circles and drew a couple of vertical lines. When I went to draw a 2 point line across the vertical lines which I will use to trim the line, the 2-point line extends infinitely through the 2 points so I am unable to trim or divide it. I have tried removing the vertical lines and closing and re-opening the drawing. Next step would be to start over and not use the vertical lines and see if that works. Any suggestions would be  appreciated.

Alan

Simple. Untick Construction Layer in Layer List. Hard to see, grey versus green.

Much thanks