RhinoPageViewPageIsActive Property

partial class Examples
{
  public static Rhino.Commands.Result ActiveViewport(Rhino.RhinoDoc doc)
  {
    Rhino.Display.RhinoView view = doc.Views.ActiveView;
    if (view == null)
      return Rhino.Commands.Result.Failure;

    Rhino.Display.RhinoPageView pageview = view as Rhino.Display.RhinoPageView;
    if (pageview != null)
    {
      string layout_name = pageview.PageName;
      if (pageview.PageIsActive)
      {
        Rhino.RhinoApp.WriteLine("The layout {0} is active", layout_name);
      }
      else
      {
        string detail_name = pageview.ActiveViewport.Name;
        Rhino.RhinoApp.WriteLine("The detail {0} on layout {1} is active", detail_name, layout_name);
      }
    }
    else
    {
      string viewport_name = view.MainViewport.Name;
      Rhino.RhinoApp.WriteLine("The viewport {0} is active", viewport_name);
    }
    return Rhino.Commands.Result.Success;
  }
}

Partial Class Examples
  Public Shared Function ActiveViewport(ByVal doc As Rhino.RhinoDoc) As Rhino.Commands.Result
    Dim view As Rhino.Display.RhinoView = doc.Views.ActiveView
    If view Is Nothing Then
      Return Rhino.Commands.Result.Failure
    End If

    Dim pageview As Rhino.Display.RhinoPageView = TryCast(view, Rhino.Display.RhinoPageView)
    If pageview IsNot Nothing Then
      Dim layout_name As String = pageview.PageName
      If pageview.PageIsActive Then
        Rhino.RhinoApp.WriteLine("The layout {0} is active", layout_name)
      Else
        Dim detail_name As String = pageview.ActiveViewport.Name
        Rhino.RhinoApp.WriteLine("The detail {0} on layout {1} is active", detail_name, layout_name)
      End If
    Else
      Dim viewport_name As String = view.MainViewport.Name
      Rhino.RhinoApp.WriteLine("The viewport {0} is active", viewport_name)
    End If
    Return Rhino.Commands.Result.Success
  End Function
End Class

import Rhino
import scriptcontext

def ActiveViewport():
    view = scriptcontext.doc.Views.ActiveView
    if view is None: return
    if isinstance(view, Rhino.Display.RhinoPageView):
        if view.PageIsActive:
            print "The layout", view.PageName, "is active"
        else:
            detail_name = view.ActiveViewport.Name
            print "The detail", detail_name, "on layout", view.PageName, "is active"
    else:
        print "The viewport", view.MainViewport.Name, "is active"


if __name__ == "__main__":
    ActiveViewport()