Clipboard: copy/paste problem

Hi, I have problem with copy and paste from clipboard. I get this error from Xamarin Studio 4.0.8:

System.ArgumentException: Lunghezza della matrice di origine insufficiente. Controllare srcIndex, la lunghezza e i limiti inferiori della matrice. in System.Array.Copy(Array sourceArray, Int32 sourceIndex, Array destinationArray, Int32 destinationIndex, Int32 length, Boolean reliable) in Mono.TextEditor.ClipboardActions.<>c__DisplayClass4.b__0(Clipboard clp, SelectionData selectionData) in GtkSharp.ClipboardReceivedFuncWrapper.NativeCallback(IntPtr clipboard, IntPtr selection_data, IntPtr data)