Returning to Video Studio 10 after a period of disuse. All went fairly well until I managed to do something which resulted in a red line appearing in the timeline as per the pic below...

As a result, I can't view any part of the (as yet rather short) compiled video as hitting 'play' takes me straight to that red lined section (which is blank)...
I am sure that this will be a simple fix, but for the life of me I can't find anything in the help section or here that points me at what this is - which probably means I'm not searching for the right term, I guess.
Any hints?
