User blog:13th madman/annoying new line glitch

I'm not sure wether this is a glitch or some bad setting, but whenever I stop typing the cursor returns to the start of the line, so that pressing enter or backspace moves the line away rather than deleting the last letter or starting a new line. It's annyoing me a lot, but I can't work out how to stop it happening at all.

Has anyone else had a problem with this, and if so how do I stop it? thanks.