Working on layout parts to PDF last night as I finally finished the fall show, and now Finale '12 is REALLY killing me.  I made a video of my despair.  I'm pretty much at my wits end at this point.  All it is doing is hanging up my computer, not letting me change anything (even force # of measures in a line, nothing.) 
[url=https://www.youtube.com/watch?v=iJw_dOVB0v8&feature=youtu.be&a]https://www.youtube.com/watch?v=iJw_dOVB0v8&feature=youtu.be&a[/url]

I've attached a download link to this little demon file if you would like to give it a try on your machine.

Kent,

I watched the video, looks like an interesting problem. It will be a couple of days before I can dive into solving the issue.

Thanks Ted,  None of my other scores are getting me thankfully, just this one, completely out of the blue.  I have created a work around, by managing parts, then extracting them 1 by 1, this gets me to nice looking parts but if I need to change something, its terrible (universally that is).  So it's not ideal for MY work flow, but it's done.  When I unclick special part extraction, everything works beautifully, I just can't get 1 staff on a page......

So I recreated the issue in another score.  I'm guessing it's partially because of the original score I was given to work off of and it's formatting.  But I really know noting.

It seems if I click the % tool to enlarge a staff in page view, if it gets too big it goes bezerk.  hangs, moves the measure, everything.  I've reposted a video to show.  [url=https://www.youtube.com/watch?v=d-gAYTyrJys]https://www.youtube.com/watch?v=d-gAYTyrJys[/url]

I just watched the second video. Watching both videos and you follow up comments leads me to agree that there is/was something wrong with the original file. BTW, there really is no need to use Special Parts Extraction any more. Working with linked parts provides many more benefits. I'll take a deeper look into the file though.

Kent,

I have examined the file. The one thing that stands out is that 'Special Part Extraction' was checked. Once I unchecked this I was able to see the entire score and edit the parts you have marked as Parts1-3. There were no signs of the problem you saw when viewing the parts in this manner.

I would second Ted's thoughts on Special Part Extraction. Linked Parts is the way to go. The issue you're having is a bug that's been around for some time.