Adobe Flash Professional CS6 Can't Preview my .GIF in a properly sized window and the stage is off

I'm working with Adobe Flash Professional CS6 after taking a class years ago and I've since forgotten most of the lessons I had learned in the distant past. For a fun home project, I just took a photo I found online and tried getting some text to scroll across the photo. Then, I have the text blinking in and out of the center of that image. I saved my work, but I can't seem to preview my work in a normal sized window after loading from Publish Preview nor could I figure out how to clean up the area surrounding the stage (where there's a black square shape protruding from the upper left side.) When I export the project into a .gif file (which is what I ultimately am working on this to accomplish,) it's only focused on the upper left side of the stage and all of my work is cut off. I don't know what to do and my knowledge is extremely limited, I apologize.