Is there any reason why I can be working on a drawing and randomly items start shifting to the right, and off of the grid alignment? I can't see obviously there's anything that I am doing wrong, but the longer I work the more things I find that have moved. It appears to be slightly progressive, so that the left hand side is all ok, but the further right I go the worse it gets. This is happening to symbols and lines/cables, which is a complete nightmare as I find myself continually realigning everything. It's almost as if the drawing is extending itself to the right.

I'm guessing since having a quick search through the forum and not finding a similar thread that no-one else has had this issue. It's a massive drawing and I really can't restart it.