Enforce maximum title length

Content becomes more readable, and therefore more accessible, if the titles and headings of the content are kept relatively short. You can set a maximum field length to enforce short titles and headings.

Setting a maximum length for one or more fields requires you to edit your Schema source. After creating a Schema and its fields, find the fields you defined in the Source tab. A typical plain-text field looks as follows:
<xsd:element name="FIELDNAME" minOccurs="1" maxOccurs="1" type="xsd:"normalizedString">
  <xsd:annotation>
    --contents of annotation section--
  </xsd:annotation>
</xsd:element>

where FIELDNAME is the name you gave to the field.

To set a maximum length for this field, first, add the following below the <xsd:annotation> section:
<xsd:simpleType>
  <xsd:restriction base="xsd:normalizedString">
    <xsd:minLength value="1"></xsd:minLength>
    <xsd:maxLength value="MAXLENGTH"></xsd:maxLength>
  </xsd:restriction>
</xsd:simpleType>

where MAXLENGTH is the maximum number of characters you want to allow for the field. Authors won't be able to save a content item if the field length exceeds this number.

Next, remove type="xsd:normalizedString" from the top-level element of the field.

After these changes, the updated XML for the field then looks like this:
<xsd:element name="FIELDNAME" minOccurs="1" maxOccurs="1">
  <xsd:annotation>
    --contents of annotation section--
  </xsd:annotation>
  <xsd:simpleType>
    <xsd:restriction base="xsd:normalizedString">
      <xsd:minLength value="1"></xsd:minLength>
      <xsd:maxLength value="MAXLENGTH"></xsd:maxLength>
    </xsd:restriction>
  </xsd:simpleType>
</xsd:element>