Cannot Browse to specific Type in Settings designer for WPF/.net Core application

When I've used Settings Designer before, I've been able to browse to find non-standard Types (e.g. uncommon enums etc) to use in my Settings via a "Browse" button at the bottom of the drop down under the "Type" column. I'm developing a WPF desktop application for .net Core and there is no Browse option as pictured below:

I did go into the code behind (Settings.Designer.cs.) and edit the code manually, but on saving, this just reverted to string. I'm guessing this may have something to do with settings also having an element in App.config and I notice it has a "serialiseAs" tag - didn't know what to put here. Exmaple of the code behind settings and App.config:

[global::System.Configuration.UserScopedSettingAttribute()]
[global::System.Diagnostics.DebuggerNonUserCodeAttribute()]
[global::System.Configuration.DefaultSettingValueAttribute("")]
public string UiTheme {
    get {
        return ((string)(this["UiTheme"]));
    }
    set {
        this["UiTheme"] = value;
    }
}

<userSettings>
    <GameBoxer.WPF.Properties.Settings>
        <setting name="UiTheme" serializeAs="String">
            <value />
        </setting>
    </GameBoxer.WPF.Properties.Settings>
</userSettings>

Does anyone know how to bring back the 'Browse'?? Or, how to correctly do it in code?

I'm using Visual Studio 2022 Community

Thanks

---

UPDATE: So, I learn that this is "By Design" in VS2022 according to MS here. IT still works in VS2019 fine! But they've taken it out of VS2022 and I can't figure how to do it in code. MS, you're one of my faves out the bunch, but sometimes, you're as mad as a box of frogs.