"The type name 'views' does not exist in the type 'orderplugin'" when I add a event to usercontrol

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C#

WPF

I'm not sure why I get this error and I have been trying a bunch of stuff.

I have this WPF UserControl that I am building:

<UserControl x:Class="OrderPlugin.Views.OrderListUserControl"
 xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
 xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
 xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
 xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
 xmlns:wpf="clr-namespace:Material.Icons.WPF;assembly=Material.Icons.WPF"
 xmlns:OrderPlugin="clr-namespace:OrderPlugin"
 xmlns:converters="clr-namespace:Core.UI.Converters;assembly=Core.UI"
 mc:Ignorable="d"
 d:DesignHeight="300" d:DesignWidth="250" MinWidth="250" >
<!-- body omitted -->
</UserControl>

This builds fine. I can start my application, see the controls. I can interact with this and any bindings to viewmodel is working without issue. Then I subscribe to an event:

<UserControl x:Class="OrderPlugin.Views.OrderListUserControl"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:wpf="clr-namespace:Material.Icons.WPF;assembly=Material.Icons.WPF"
xmlns:OrderPlugin="clr-namespace:OrderPlugin"
xmlns:converters="clr-namespace:Core.UI.Converters;assembly=Core.UI"
mc:Ignorable="d"
d:DesignHeight="300" d:DesignWidth="250" MinWidth="250" Loaded="OrderListUserControl_OnLoaded" >

<!-- body omitted -->
</UserControl>

And when I Build i get the error:

Error CS0426 : The type name 'Views' does not exist in the type 'OrderPlugin'

Why? I have done this in other plugins project and user controls and it works fine there.

What I have tried:

I have tried cleaning my project. I have made sure the csproj file looks the same as the others that works fine.

I have tried moving the files to the root of the project, but that just moved the problem:

Error CS0426 : The type name 'OrderListUserControl' does not exist in the type 'OrderPlugin'

So it seems if the UserControl is in its own folder/namespace does not really affect it.

So how does the reference get broken because I add an event?