You are probably dealing with http://dada.perl.it/gui_docs/Textfield.html

MaxLength([CHARS])

    Limits the number of characters that the Textfield accept to CHARS
+, or returns the current limit if no argument is given. To remove the
+ limit (eg. set it to the maximum allowed which is 32k for a single-l
+ine Textfield and 64k for a multiline one) set CHARS to 0.
[download]