added enum for Protocol and TerminalView Types,

implemented selection of TerminalViewType in UI,
added BindingProxy to provide DataContext to elements that are not in the VisualTree of the UI

MultiTerm.Core/Common/ProtocolType.cs

@@ -0,0 +1,30 @@
+using System.ComponentModel;
+
+namespace MultiTerm.Core.Common;
+
+public enum ProtocolType
+{
+    /// <summary>
+    /// Serial Protocol
+    /// </summary>
+    [Description("Serial")]
+    Serial,
+
+    /// <summary>
+    /// USB HID Protocol
+    /// </summary>
+    [Description("USB HID")]
+    UsbHid,
+
+    /// <summary>
+    /// TCP Protocol
+    /// </summary>
+    [Description("TCP")]
+    Tcp,
+
+    /// <summary>
+    /// UDP Protocol
+    /// </summary>
+    [Description("UCP")]
+    Udp
+}

MultiTerm.Core/Common/TerminalViewType.cs

@@ -0,0 +1,18 @@
+using System.ComponentModel;
+
+namespace MultiTerm.Core.Common;
+
+public enum TerminalViewType
+{
+    /// <summary>
+    /// SendReceive View
+    /// </summary>
+    [Description("Send/Receive")]
+    SendReceive,
+
+    /// <summary>
+    /// Console View
+    /// </summary>
+    [Description("Console")]
+    Console
+}

MultiTerm.Core/ViewModel/ITerminalViewModel.cs

@@ -1,4 +1,6 @@
-namespace MultiTerm.Core.ViewModel;
+using MultiTerm.Core.Common;
+
+namespace MultiTerm.Core.ViewModel;
 
 public interface ITerminalViewModel
 {
@@ -7,6 +9,16 @@ public interface ITerminalViewModel
     /// </summary>
     string Title { get; }
     
+    /// <summary>
+    /// Type of view.
+    /// </summary>
+    TerminalViewType ViewType { get; }
+
+    /// <summary>
+    /// Type of Protocol.
+    /// </summary>
+    ProtocolType ProtocolType { get; }
+
     /// <summary>
     /// Request Closing of Terminal.
     /// </summary>

MultiTerm.Core/ViewModel/SendReceiveViewModel.cs

@@ -1,7 +1,15 @@
-namespace MultiTerm.Core.ViewModel;
+using MultiTerm.Core.Common;
+
+namespace MultiTerm.Core.ViewModel;
 
 public partial class SendReceiveViewModel : TerminalViewModel
 {
     public override string Title => "SendReceive Tab";
+    public override TerminalViewType ViewType => TerminalViewType.SendReceive;
+
+    public SendReceiveViewModel() : base(ProtocolType.Serial) // TODO implement Protocol initialization
+    {
+        
+    }
 
 }

MultiTerm.Core/ViewModel/ShellViewModel.cs

@@ -29,6 +29,12 @@ public partial class ShellViewModel : ObservableObject
     private NewlineSeparatorType defaultSendNewlineSeparator = NewlineSeparatorType.None;
     #endregion
 
+    #region New Terminal Context Menu
+    [ObservableProperty]
+    private TerminalViewType selectedTerminalViewType = TerminalViewType.SendReceive;
+
+    #endregion
+
     public ShellViewModel(IAbstractFactory<SendReceiveViewModel> sendReceiveViewModelFactory)
     {
         this.sendReceiveViewModelFactory = sendReceiveViewModelFactory;
@@ -36,7 +42,8 @@ public partial class ShellViewModel : ObservableObject
         this.AppendTerminal(this.sendReceiveViewModelFactory.Create());
     }
 
-    public void AppendTerminal(ITerminalViewModel newTerminal)
+    [RelayCommand]
+    private void AppendTerminal(ITerminalViewModel? newTerminal)
     {
         // guard null value
         if(newTerminal == null) { return; }
@@ -50,11 +57,11 @@ public partial class ShellViewModel : ObservableObject
 
     private void Terminal_ClosingEvent(object? sender, EventArgs e)
     {
-        if(sender is not ITerminalViewModel tvm) { throw new ArgumentException(nameof(sender)); }
+        if(sender is not ITerminalViewModel tvm) { throw new ArgumentException($"{nameof(Terminal_ClosingEvent)} failed to convert sender to {nameof(ITerminalViewModel)}"); }
         this.RemoveTerminal(tvm);
     }
 
-    public void RemoveTerminal(ITerminalViewModel terminalToRemove)
+    private void RemoveTerminal(ITerminalViewModel terminalToRemove)
     {
         // guard null value
         if(terminalToRemove == null) { return; }
@@ -73,7 +80,7 @@ public partial class ShellViewModel : ObservableObject
     }
 
     [RelayCommand]
-    public void TestButtonClicked()
+    private void TestButtonClicked()
     {
         this.DefaultReceiveNewlineSeparator = NewlineSeparatorType.CR_LF;
     }

MultiTerm.Core/ViewModel/TerminalViewModel.cs

@@ -1,14 +1,22 @@
 using CommunityToolkit.Mvvm.ComponentModel;
 using CommunityToolkit.Mvvm.Input;
+using MultiTerm.Core.Common;
 
 namespace MultiTerm.Core.ViewModel;
 
 public abstract partial class TerminalViewModel : ObservableObject, ITerminalViewModel
 {
     public abstract string Title { get; }
+    public abstract TerminalViewType ViewType { get; }  
+    public ProtocolType ProtocolType { get; private set; }
 
     public event EventHandler? ClosingEvent;
 
+    public TerminalViewModel(ProtocolType protocolType)
+    {
+        this.ProtocolType = protocolType;
+    }
+
     /// <summary>
     /// Method to override if any closing actions are required.
     /// Closing can be cancelled using the return value.

MultiTerm.Wpf/App.xaml.cs

@@ -3,6 +3,7 @@ using Microsoft.Extensions.Hosting;
 using MultiTerm.Core.ViewModel;
 using Common.StartupHelpers;
 using System.Windows;
+using MultiTerm.Core.Common;
 
 namespace MultiTerm.Wpf;
 

MultiTerm.Wpf/Controls/SingleSelectSubMenu.cs

@@ -105,7 +105,7 @@ public class SingleSelectSubMenu : MenuItem
 
     /// <summary>
     /// Options Source Changed Handler.
-    /// Builds list with options and adds them to parent MenuItem (must be Menu Item!).
+    /// Builds list with options and adds them to parent ItemsControl (must be subtype of ItemsControl).
     /// Registers menu Items in locally stored list.
     /// Cannot handle changing OptionsSources. Internal list will build up.
     /// </summary>
@@ -114,7 +114,7 @@ public class SingleSelectSubMenu : MenuItem
         // extract instance and guard null
         if (d is not SingleSelectSubMenu sssm) { return; }
         // extract parent instance of SSSM and guard null
-        if (sssm.Parent is not MenuItem parent) { return; }
+        if (sssm.Parent is not ItemsControl parent) { throw new ArgumentException($"Wrong parent type."); }
 
         // iterate through new OptionsSource Values and build up list of menuItems
         foreach (var item in (IEnumerable)e.NewValue)
@@ -123,6 +123,7 @@ public class SingleSelectSubMenu : MenuItem
             var converter = new EnumDescriptionToMenuItemConverter();
             var newMenuItem = (MenuItem)converter.Convert(item, typeof(MenuItem), new object(), CultureInfo.CurrentCulture);
             newMenuItem.IsCheckable = true;
+            newMenuItem.StaysOpenOnClick = true;
 
             // assign to event handler and register in dictionary
             newMenuItem.Checked += OnAnyItemChecked;

MultiTerm.Wpf/Helpers/BindingProxy.cs

@@ -0,0 +1,27 @@
+using System.Windows;
+
+namespace MultiTerm.Wpf.Helpers;
+
+/// <summary>
+/// Serves as a Proxy to provide DataContext for Elements that are not part of the VisualTree.
+/// From: https://thomaslevesque.com/2011/03/21/wpf-how-to-bind-to-data-when-the-datacontext-is-not-inherited/
+/// </summary>
+public class BindingProxy : Freezable
+{
+    #region Overrides of Freezable
+    protected override Freezable CreateInstanceCore()
+    {
+        return new BindingProxy();
+    }
+    #endregion
+
+    public object Data
+    {
+        get { return (object)GetValue(DataProperty); }
+        set { SetValue(DataProperty, value); }
+    }
+
+    // Using a DependencyProperty as the backing store for Data.  This enables animation, styling, binding, etc...
+    public static readonly DependencyProperty DataProperty =
+        DependencyProperty.Register("Data", typeof(object), typeof(BindingProxy), new UIPropertyMetadata(null));
+}

MultiTerm.Wpf/View/ShellView.xaml

@@ -9,6 +9,7 @@
              xmlns:vm="clr-namespace:MultiTerm.Core.ViewModel;assembly=MultiTerm.Core"
              xmlns:v="clr-namespace:MultiTerm.Wpf.View"
              xmlns:core_common="clr-namespace:MultiTerm.Core.Common;assembly=MultiTerm.Core"
+             xmlns:helpers="clr-namespace:MultiTerm.Wpf.Helpers"
              mc:Ignorable="d" 
              d:DesignHeight="600" d:DesignWidth="1200">
     <UserControl.Resources>
@@ -23,6 +24,13 @@
                 <x:Type TypeName="core_common:NewlineSeparatorType" />
             </ObjectDataProvider.MethodParameters>
         </ObjectDataProvider>
+        <ObjectDataProvider x:Key="TerminalViewTypeValues"
+                        ObjectType="{x:Type sys:Enum}"
+                        MethodName="GetValues">
+            <ObjectDataProvider.MethodParameters>
+                <x:Type TypeName="core_common:TerminalViewType" />
+            </ObjectDataProvider.MethodParameters>
+        </ObjectDataProvider>
 
     </UserControl.Resources>
 
@@ -58,7 +66,61 @@
             <MenuItem Header="_About"/>
         </Menu>
         <StackPanel Orientation="Vertical" DockPanel.Dock="Left" Width="150">
+            <Button Name="AddNewTabButton" Content="Add new Tab">
+                <Button.Resources>
+                    <!-- Binding Proxy to provide DataContext to elements within ContextMenu -->
+                    <helpers:BindingProxy x:Key="proxy" Data="{Binding}"/>
+                </Button.Resources>
+                <Button.ContextMenu>
+                    <ContextMenu x:Name="MainContextMenu" PlacementRectangle="{Binding RelativeSource={RelativeSource Self}}">
+                        <!-- View types -->
+                        <controls:SingleSelectSubMenu Title="View type"
+                            OptionsSource="{Binding Source={StaticResource TerminalViewTypeValues}}"
+                            SelectedMenuItem="{Binding Data.SelectedTerminalViewType, Mode=TwoWay, Source={StaticResource proxy},
+                                               Converter={StaticResource EnumDescriptionConverter}}">
+                        </controls:SingleSelectSubMenu>
+                        
+                        <Separator/>
+                        <MenuItem Header="Protocol" IsEnabled="False"/>
+                        
+                        <!-- Protocol types -->
+                        <MenuItem Header="Serial"
+                            Command="{Binding Data.AppendTerminalCommand, Source={StaticResource proxy}}">
+                            <!--TODO implement parameter CommandParameter="{Binding RelativeSource={RelativeSource Self}}">-->
+                        
+                        </MenuItem>
+                        <MenuItem Header="USB HID" />
+                        <MenuItem Header="TCP" />
+                        <MenuItem Header="UCP" />
+                    </ContextMenu>
+                </Button.ContextMenu>
+
+                <Button.Triggers>
+                    <EventTrigger SourceName="AddNewTabButton" RoutedEvent="Button.Click">
+                        <BeginStoryboard>
+                            <Storyboard>
+                                <ObjectAnimationUsingKeyFrames Storyboard.TargetName="MainContextMenu" Storyboard.TargetProperty="(ContextMenu.IsOpen)">
+                                    <DiscreteObjectKeyFrame KeyTime="0:0:0">
+                                        <DiscreteObjectKeyFrame.Value>
+                                            <sys:Boolean>True</sys:Boolean>
+                                        </DiscreteObjectKeyFrame.Value>
+                                    </DiscreteObjectKeyFrame>
+                                </ObjectAnimationUsingKeyFrames>
+                            </Storyboard>
+                        </BeginStoryboard>
+                    </EventTrigger>
+                </Button.Triggers>
+            </Button>
+            
+            <!--<RibbonMenuButton x:Name="newTerminalMenu" Label="Add new Tab" Background="Gray">
+                <RibbonRadioButton Label="SendReceive">
+                    
+                </RibbonRadioButton>
+                <RibbonRadioButton Label="Console">
 
+                </RibbonRadioButton>
+                <RibbonSeparator/>
+            </RibbonMenuButton>-->
         </StackPanel>
         <TabControl DockPanel.Dock="Right"
             x:Name="terminalTabControl"
@@ -74,6 +136,8 @@
                             <Button.Style>
                                 <Style TargetType="Button" x:Name="CloseButtonStyle">
                                     <Setter Property="Visibility" Value="Visible"/>
+                                    <Setter Property="Background" Value="Transparent"/>
+                                    <Setter Property="BorderBrush" Value="Transparent"/>
                                 </Style>
                             </Button.Style>
                         </Button>