gui construction - Dynamic not responding to Refresh TrackedSymbols

I am attempting to creating a UI dialogue that updates itself as selections are made. The issue is the UI is not updating itself even though the dependent variables are being updated. A very minimal example follows.

v =.;
Panel[
 Column@{
   Row[{"Pick", 
     CheckboxBar[Dynamic@v, # -> IntegerName@# & /@ Range[3]]}],
   Dynamic[
    Refresh[

     If[ValueQ[v],
      v + 1,
      "Pick something"
      ],
     TrackedSymbols :> {v}
     ]
    ]}
 ]

What I am expecting to happen is that once v is assigned a value that the If will update to show the calculation. However, v is updated but the Dynamic does not update.

In the actual case the user select a value from a PopupMenu. This value is used to query a database with the resultset being used in the next PopupMenu. Similar to the above except there are some function calls. The variable v must initially be clear.

Ideas?

Update

I had some to and fro emails with WRI and I think they are looking into why ValueQ does not re-evaluate in the If. I have worked out that I can use v = Null; to start and v =!= Null in the If to get things to work as expected.

Comments

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