This, for me, is the number one missing feature.
Often we presents the users with a large list of operations
until this PR they had to scroll through the list every time (because they often repeat commands).
Now we simply set the last command they executed as the default.

Just tested this and it works great:

var fruit = AnsiConsole.Prompt(
    new SelectionPrompt<string>()
        .Title("What's your [green]favorite fruit[/]?")
        .PageSize(10)```
+       .DefaultValue("Banana") // <--- Setting the default value
        .MoreChoicesText("[grey](Move up and down to reveal more fruits)[/]")
        .AddChoices(new[] {
            "Apple", "Apricot", "Avocado", 
            "Banana", "Blackcurrant", "Blueberry",
            "Cherry", "Cloudberry", "Cocunut",
        }));

AnsiConsole.WriteLine($"I agree. {fruit} is tasty!");

Its not pretty but as a workaround (like if you need this feature now) you can order your default to the top and even use converter to highlight to user why it is not in the expected order (i.e. alphabetical or whatever)

var mode = AnsiConsole.Prompt(
    new SelectionPrompt<MyEnum>()
        .Title("Pick an enum")
        .AddChoices(Enum.GetValues<MyEnum>()
            // Make SomeValue default by having it first
            .OrderByDescending(e=>e == MyEnum.SomeValue)
            .ThenBy(e=>e))
        .UseConverter(mode =>mode == MyEnum.SomeValue ? mode.ToString() +" (Default)" : mode.ToString())
        .WrapAround(true));

This PR really works and should be merged, it's been nearly a year.
(But there's not much activity on this project anymore)

This could close one of the highest ranking issues on the priority board.

#508