Using SE (ST4) happens to me a strange thing.
When I edited a sketch the relationships inside it are not recognized, are shown but if I try to select them (or delete them) they are not selectable.
If I delete a line, or use the command "update sketch" all comes back to normal, but if I close and reopen the file the "strange thing" come back.
I updated the video card driver and last MP
Have you ever seen a situation like that???What's the causes???