In what way were you "messing with themes"? were you selecting different themes or were you attempting to modify the theme template itself?
changing from theme to theme useing my layout - didnt like any - didnt realize the time it would take to change back to original layout - fyi, i started deleting the fields and field names that have problem and replacing - took care of extra line problem - thanks
Note that when you select one theme after the other in the same file, the file grows a bit in size with each new theme selection and this increase in file size cannot be reversed. You may want to take a copy of your file, play with different themes and then, when you decide on the one you want, open your original copy and make that single theme change.
For More Information see: Repeated Theme Changes Bloats File Size
This is one of many acknowledged bugs that can be found in the Known Bug List thread here in the Report an Issue section of the forum.
It can also be downloaded as a database file from: https://www.dropbox.com/s/jt09b82i0xijbu3/FMP%20Bugs.zip