How can I get a partially translated XLIFF to show translations in target column?

I have an XLIFF file that is partially translated. We need to translate the strings that are not yet translated. The trans-unit/translate attribute is set correctly and the read-only processing works correctly. However the target column always contains a copy of the source column text. It does not show the text in the target element. What am I doing wrong?

I expected the following:

Target column contains the translated text if already translated and be read-only if translate="no"

Target column is empty if no translation exists and the string is not read-only when if translate="yes"

Best regards

Robert Bevington