class Class<T>
{
  public B(int p)
  {
  }
}

class C
{
  void Foo()
  {
    new Cl<string>();
  }
}

Invoke completion after "new Cl" and choose "Class<T>". Press Tab. It removes existing type arguments (although it did not highlight them with pink highlighting!). It should not replace existing type arguments when the type has type arguments.

Another case is when constructor of "Class<T>" has no parameters. In this case pink highlighting and the behaviour are consistent but I believe it should not replace type arguments in this case too.