Afternoon all!

A quick question which I hope someone might be able to help with.

I've been working on a project that I'm due to deliver on Saturday (it's now Tuesday), involving putting lots of sections of different videos together, along with music. All has been going well so far - until I tried using secondary color correction.

I wanted to add orange color to some black-and-white movie footage of a burning building, to make the flames stand out.

The colour came out just as I wanted, but in fullscreen playback in the MEP preview monitor and when exporting to MPEG, the size of the video image was only occupying a portion of the screen, when it should have been fullscreen. Thus:

  

The orange-and-black image in the top left corner should be occupying the full screen, obscuring the background image which just happens to be on another track on the timeline. (NB the presence or absence of an image on another track makes no difference - whilst trying to fix the problem I created a new MEP project just to create this one effect on this one clip, and still had the same problem.)

I have also tried to "confirm" the image size and section using the relevant options in the video effects pool, but this isn't doing the trick either.

FWIW I have been able to export the original black and white clip in the correct size. It seems to me that the software is taking the size of the image in my preview monitor and using this in the fullscreen playback and export instead of the size of image I actually wanted - but only after the secondary colour correction is applied.

I have been so enjoying using MEP 2013, but yet again I've found a weird bug...

Any ideas? Thanks in advance! 
 

FYI My PC spec is good (Core i5, 16GB, etc.) - I have already made a number of videos using various versions of MEP without any troubles.