Sounds to me like you describe a typical inheritance relationship, i.e. "Label IS-A Control". In this case, you should really consider using class types. GUI programming is often considered a strength of object-oriented programming.

That said, if you really absolutely want to use records here, you could make it work with interfaces:

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// Marker interface for controls
type IControl = interface end

type Control =
   { ID: string; SkinID: string; Controls: seq<IControl> }
   interface IControl

type ILabel = 
  inherit IControl

type Label =
   { Text: string }
   interface ILabel

let label = { Text="hello" }
let nestedControl = { ID="2"; SkinID="3"; Controls=[] }

let control = { ID="1"; SkinID="2"; Controls=[label; nestedControl]}

On the other hand, I'm not sure whether custom interfaces for records are officially part of the language. It says on MSDN:

"Records are basically simple aggregates of values, without separate constructors that can perform custom actions, without hidden fields, and without inheritance or interface implementations." ( [link:msdn.microsoft.com] )