diff --git a/Application.xaml.vb b/Application.xaml.vb
index e939894..9ff51a6 100644
--- a/Application.xaml.vb
+++ b/Application.xaml.vb
@@ -10,10 +10,6 @@ Class Application
    ' can be handled in this file.
    Protected Overrides Sub OnStartUp(e As System.Windows.StartupEventArgs)
       MyBase.OnStartup(e)
-
-      'Dim TempCurrentDomain As AppDomain = AppDomain.CurrentDomain
-      'AddHandler TempCurrentDomain.UnhandledException, AddressOf TempCurrentDomain_UnhandledException
-
       ShutdownMode = System.Windows.ShutdownMode.OnMainWindowClose
       ' Creo la View principale
       Dim MainWndView As New MainWindow
diff --git a/ProjectPage/MachGroupPanel/MachGroupPanelView.xaml b/ProjectPage/MachGroupPanel/MachGroupPanelView.xaml
index 94f042e..026d5e6 100644
--- a/ProjectPage/MachGroupPanel/MachGroupPanelView.xaml
+++ b/ProjectPage/MachGroupPanel/MachGroupPanelView.xaml
@@ -48,9 +48,9 @@
          </ListBox.ItemTemplate>
       </ListBox>
 
-      <Button Content="+" Height="20" Width="20" VerticalAlignment="Center"
+      <Button Content="+" Height="20" Width="20" VerticalAlignment="Center" Focusable="False"
          Margin="3,0,5,0" Command="{Binding AddMachGroupCommand}" Grid.Column="1"/>
-      <Button Content="-" Height="20" Width="20" VerticalAlignment="Center"
+      <Button Content="-" Height="20" Width="20" VerticalAlignment="Center" Focusable="False"
          Margin="0,0,5,0" Command="{Binding RemoveMachGroupCommand}" Grid.Column="2"/>
 
    </Grid>
diff --git a/ToolsDbWindow/ToolTreeView.vb b/ToolsDbWindow/ToolTreeView.vb
index 52a8234..9c2a44f 100644
--- a/ToolsDbWindow/ToolTreeView.vb
+++ b/ToolsDbWindow/ToolTreeView.vb
@@ -1102,9 +1102,14 @@ Public Class ToolTreeViewItem
       NotifyPropertyChanged("UserNotes")
       m_IsModifiedUserNotes = False
       EgtTdbGetCurrToolParam(MCH_TP.TCPOS, sValue)
-      m_SelectedTcPos = sValue
+      If m_TcPosList.Contains(sValue) Then
+         m_SelectedTcPos = sValue
+         m_IsModifiedSelectedTcPos = False
+      Else
+         m_SelectedTcPos = Nothing
+         EgtTdbSetCurrToolParam(MCH_TP.TCPOS, String.Empty)
+      End If
       NotifyPropertyChanged("SelectedTcPos")
-      m_IsModifiedSelectedTcPos = False
       EgtTdbGetCurrToolParam(MCH_TP.UUID, sValue)
       m_Uuid = sValue
       ' Ora che tutti i parametri sono aggiornati, aggiorno il disegno