For some reason, out of the blue, I cannot do this on a drawing, a drawing I have been working on for days.  When I pass over the intersecting line, no green x appears, it’s as if the line wasn’t there. Now to confuse things further - it only occurs on some lines in the drawing, not all lines. To get around this - I have to use the “trim” option to reduce the length of a line - but that’s a pain.

Any idea on what’s happened?  Have I hit a button or feature accidentally?  I have rebooted the file, repaired the file, neither fixed. This happened once before a few months ago as well on a different file, I just lived with it then. I’m using AutopCAD 2012 Lite.

Anyone know what may have happened.