Mattias yes it’s exactly that. I think the software should understand where a cut is “logical” and alow a simple paste to recover the original file without having to bounce or extend margins of one of the cuted files… Seems pretty simple 
Of course if one of the truncated region has been midified it’s different. But what i’m talking about is a basic cut in the file that you want to remove and it is not in the undo list anymore, or undo order (maybe yoy did impirtant things after it)