I'm joining this thread a little late, so I apologise if this solution has
already been dismissed.

Does your component inherit from System.ComponentModel.Component
If not does it implement IComponent.

If so then you do not need any attributes to get your property to behave as
you described.

As a simple example, add a UserControl to your project.

Add this code to the standard code already in the class.

\\\
private MyComponent componentProperty = null;

public MyComponent MyProperty
{
 get
 {
   return componentProperty;
 }
 set
 {
   componentProperty = value;
 }
}
///

now add a new Component (called MyComponent) to your project.

Build the project.

add an instance of the usercontrol and several instances of MyComponent to
your form.

your UserControls MyProperty should display (none) and in it's dropdown list
should be a list of all the MyComponent objects on the form.

no need for TypeConverters at all, unless your component class does not
implement IComponent.