Editor for specific inherited class ?

I want to add editor for a specific inherited class, but not for other inherited class. How to do that without showing the ... button to show modal dialog ?

class A1Editor : UITypeEditor {}

class A {}
[Editor(typeof(A1Editor),typeof(UITypeEditor))]
class A1 {}
class A2 {}


class B
{
   public A A { get; set; }
}

If I put EditorAttribute in A class it is works, but I dont want the ... button shown for A2 class.

Is that possible ?

It's hard to be advanced programmer