You didn't state the version of filemaker you are using, but I will assume 12. You need to change the theme to Basic Classic.
Sorry - FileMaker Pro 12.ov4. And thank you. Basic Classic what I started with and I haven't a clue how the theme got changed to something else. But, of course, when I changed it back, it works just fine. The next time something starts to go weird in a layout, you know what I'll check first!