Symptoms

Populating a Picker Control defaults the Picker control with a value if resolve rule called in a rule
 

Diagnoses

When a Picker control is added to a view, a default when control is resolved rule is added to the view.
This can then be called from the View's Initialise rule to populate the control with data.

However, if you don't want your control to populate immediately you can at a later stage execute the "when control is resolving rule" in order to populate the control.
When that happens the picker control is populated with one of the values in the data source by default.
This should not happen as the user should be presented with a blank box in order to select their value.

 

Resolution

A bug was logged for this issue
Workaround:

Add a condition = if picker contains a value

then excute the When picker is resolving