text box size

I have been using acorbat Pro for a few months to create forms for our office. Suddenly last week whenever I create a text box I am unable to shrink it enough to fit into the lines on my forms! I can't make them less than approx. 1.2 in tall. Even if I copy a text box (that is smaller) from another form I can't shrink the height of it? Any suggestions on settings I may have inadvertantly changed that would cause this?