orange bar on timeline in export

I must have done something odd - now getting an orange in/out bar through the top of timeline when I try to export, and it won't let me select in or out points. Not sure if it will export ok - trying now. Any ideas what this orange line means? or how I can get rid of it ...

It's rendered out as a long series of small mp4s. I am confused!

I think you chose Individual Clips in the Render Settings.

thanks you so much! I was going a little mad. 5 o'clock Friday afternoon (I'm in New Zealand) and I just need to render something out and go home!
Cheers
rob