Populate a text field based on value in a dropdown doesn't work

Hey,

I've read other questions about this on the forums, but I can't get it working.

On my form, I'm trying to populate a rich text field 'Description' with a text template, based on the selection made in drop down list named 'Service'.

In SharePoint, I have a second list called 'Services' which contains 2 columns, Title and Template. I'm trying to load the corresponding "template" based on the Service selection. The Service column in the form library is a lookup field displaying the Title column as a dropdown.

So I made a rule on 'Service' dropdown to update another field upon change.

I do the following, but despite many tries the Description field is never updated accordingly.

This is what I do :

1. In Rule Details, define 'Set a field value', 'Description' and click on the Fx button
2. In Insert a Formula, click 'Insert Field or Group'
3. Select the data source containing the template column and select the column 'Template'
4. Click on 'Filter Data'
5. Click on 'Add'
6. Set the filter as Title (from the same data connection) is equal to
7. Select the Service field from the Main data connection

Eventually my formula is : Template[Title = Service]

XPath displays this : ../../../dfs:dataFields/d:SharePointListItem_RW/d:Template[../d:Title = xdXDocument:get-DOM()/dfs:myFields/dfs:dataFields/my:SharePointListItem_RW/my:Service]

I've tried different filters, Title=Title etc.... none of them work

Am i doing something wrong ?

Thanks in advance