Recently, while experimenting with strongly-typed form helpers of MVC, I found a bug.
I posted a question at SO, but with no luck so far.
Generally, looks like DropDownFor is broken when trying to bind collection of form drop downs.
I have a workaround in form of using non-typed helper, but anyway hope to get things sorted out with strongly-typed one.

So. The bug.
I have a view with 1 dropdown generated from Model property and 3 additional dropdowns that are generated from array property.

@Html.DropDownListFor(m => m.AgentType, Model.AgentTypeListItems)
@for (int i = 0; i < Model.AgentTypes.Length; i++)
{
    @Html.DropDownListFor(m => m.AgentTypes[i], Model.AgentTypeListItems)
}

The controller method initializes AgentTypeListItems collection + sets default values for AgentType dropdown and 3 dropdowns for the collection:

var model = new OptionsViewModel();
 
// for DropDownListFor
model.AgentTypeListItems = new[]
{
    new SelectListItem { Text = "1", Value = "1" }, 
    new SelectListItem { Text = "2", Value = "2" },
    new SelectListItem { Text = "3", Value = "3" },
};
 
// 1 dropdown in the model
model.AgentType = "2";
 
// 3 dropdowns in array
model.AgentTypes = new[] { "3", "2", "1" };
 
return View(model);

The model class:

public class OptionsViewModel
{
    public SelectListItem[] AgentTypeListItems { get; set; }
    public string AgentType { get; set; }
    public string[] AgentTypes { get; set; }
}

When I open it in browser I get “2″ everywhere though AgentTypes array was initialized with different values(!):

When I replace DropDownListFor with TextBoxFor:

@Html.TextBoxFor(m => m.AgentTypes[i])

I get the correct values in the inputs (!):

this is how it should be

It means the TextBoxFor works as expected, but DropDownListFor doesn’t.
Will try to post the issue into MVC project bugtracker.