Formula field not updated in Child form (Subform)

Formula field not updated in Child form (Subform)

Hi,

I have a Parent form (myParentForm) with the subform : myChildForm.
In myChildForm I have a Formula field using the Lookup field related to myParentForm (this formula is to display a directlink to myParentForm record : href="http://....../" + input.<LookupField_to_myParentField>

When I add rows in the subform, Formula field in myChildForm is not recalculated : href above stays with http://....../null instead of http://....../0123456.
Can you make those formula fields update ?

I know some workarround to make this work, but not so logical...


Thanks !