Weird. Doesn't seem to be the code in the front end either. The maxlength already was 255.
(By the way, it is not an extended field but one of the standard custom_string fieds)
<DIV class="Size-Large" iwtype="field-string" fieldid="CUSTOM_STRING_4" iwpropclass="class" entitytype="6" iwpropentitytype="entitytype" addedByDesigner="1"><LABEL for=CUSTOM_STRING_4 iwpropdisplay="display">Incident Title<SPAN class="Mandatory" ieRequiredStar="1"> *</SPAN></LABEL><INPUT id=CUSTOM_STRING_4 class="Field" tabIndex=1 maxLength=255 name=CUSTOM_STRING_4 ismReadOnly="False" iwpropmandatory="ismMandatory" iwpropreadonly="ismReadOnly" ref="406" iwpropref="ref" iwpropid="id" ismMandatory="true" iwpropeditmask="maskid"></DIV></TD></TR>
More suggestions most welcome!
Thanks