Default value 0 for number field is not visible

demodb.xml

<plominodatabase id="demodb">
  <design>
    <element id="formInteger" title="Integer" type="PlominoForm">
      <id type="Products.Archetypes.Field.StringField">formInteger</id>
      <onCreateDocument type="Products.Archetypes.Field.TextField"><![CDATA[]]></onCreateDocument>
      <onOpenDocument type="Products.Archetypes.Field.TextField"><![CDATA[]]></onOpenDocument>
      <beforeSaveDocument type="Products.Archetypes.Field.TextField"><![CDATA[]]></beforeSaveDocument>
      <onSaveDocument type="Products.Archetypes.Field.TextField"><![CDATA[]]></onSaveDocument>
      <onDeleteDocument type="Products.Archetypes.Field.TextField"><![CDATA[]]></onDeleteDocument>
      <onSearch type="Products.Archetypes.Field.TextField"><![CDATA[]]></onSearch>
      <beforeCreateDocument type="Products.Archetypes.Field.TextField"><![CDATA[]]></beforeCreateDocument>
      <FormLayout type="Products.Archetypes.Field.TextField"><![CDATA[<p><span class="plominoLabelClass">integer</span><span class="plominoFieldClass">integer</span></p>]]></FormLayout>
      <FormMethod type="Products.Archetypes.Field.TextField"><![CDATA[Auto]]></FormMethod>
      <DocumentTitle type="Products.Archetypes.Field.TextField"><![CDATA[]]></DocumentTitle>
      <DynamicDocumentTitle type="Products.Archetypes.Field.BooleanField">False</DynamicDocumentTitle>
      <StoreDynamicDocumentTitle type="Products.Archetypes.Field.BooleanField">False</StoreDynamicDocumentTitle>
      <DocumentId type="Products.Archetypes.Field.TextField"><![CDATA[]]></DocumentId>
      <ActionBarPosition type="Products.Archetypes.Field.StringField">TOP</ActionBarPosition>
      <HideDefaultActions type="Products.Archetypes.Field.BooleanField">False</HideDefaultActions>
      <HideInMenu type="Products.Archetypes.Field.BooleanField">False</HideInMenu>
      <isSearchForm type="Products.Archetypes.Field.BooleanField">False</isSearchForm>
      <isPage type="Products.Archetypes.Field.BooleanField">False</isPage>
      <isMulti type="Products.Archetypes.Field.BooleanField">False</isMulti>
      <SearchView type="Products.Archetypes.Field.StringField"/>
      <SearchFormula type="Products.Archetypes.Field.TextField"><![CDATA[]]></SearchFormula>
      <Position type="Products.Archetypes.Field.IntegerField"/>
      <ResourcesJS type="Products.Archetypes.Field.TextField"><![CDATA[]]></ResourcesJS>
      <ResourcesCSS type="Products.Archetypes.Field.TextField"><![CDATA[]]></ResourcesCSS>
      <excludeFromNav type="Products.Archetypes.Field.BooleanField">False</excludeFromNav>
      <elements>
        <element id="integer" title="Integer Number" type="PlominoField">
          <id type="Products.Archetypes.Field.StringField">integer</id>
          <FieldType type="Products.Archetypes.Field.StringField">NUMBER</FieldType>
          <FieldMode type="Products.Archetypes.Field.StringField">EDITABLE</FieldMode>
          <isDynamicField type="Products.Archetypes.Field.BooleanField">False</isDynamicField>
          <Formula type="Products.Archetypes.Field.TextField"><![CDATA[return 0]]></Formula>
          <FieldReadTemplate type="Products.Archetypes.Field.StringField"/>
          <FieldEditTemplate type="Products.Archetypes.Field.StringField"/>
          <Mandatory type="Products.Archetypes.Field.BooleanField">False</Mandatory>
          <ValidationFormula type="Products.Archetypes.Field.TextField"><![CDATA[]]></ValidationFormula>
          <ToBeIndexed type="Products.Archetypes.Field.BooleanField">False</ToBeIndexed>
          <IndexType type="Products.Archetypes.Field.StringField">DEFAULT</IndexType>
          <HTMLAttributesFormula type="Products.Archetypes.Field.TextField"><![CDATA[]]></HTMLAttributesFormula>
        </element>
      </elements>
    </element>
  </design>
</plominodatabase>