If I define a ConfigurableFormPanel with a repeater with 'min-size' at 1, then call the #setValues() method with no entry, the repeater is initially set with no entry
But if I call the #isValid method, it returns true.

So,

1. EITHER the setValues() must initialize with the 'min-size' or 'initial-size' (which I don't think it is the good solution, the current behavior is good from my point of view),
2. EITHER the #isValid() method must be overriden and do a thing like :

   formPanel.getRepeaters().each.getItems.length € [minSize, maxSize]