pentaho/pentaho-kettle — pull request #326 by prakapenka (2014-02-26 10:52:06+00:00)
Title: PDI-11420 - Cannot reopen Mapping (sub-transformation) step after saving with blank value for fieldname to target step.

Since Kettle allow empty names for fields, in case of mapping contains 'Name' to '' mapping - this will be correct case.
If somehow existing transformation already has 'null' value this will be replaced by empty String on UI.