diff --git a/ToolsDbWindow/ToolTreeView.vb b/ToolsDbWindow/ToolTreeView.vb
index f0c4bc7..7f5b5f8 100644
--- a/ToolsDbWindow/ToolTreeView.vb
+++ b/ToolsDbWindow/ToolTreeView.vb
@@ -58,7 +58,7 @@ Public Class ToolTreeViewItem
    Inherits InheritableTreeViewItem
    Implements IDataErrorInfo
 
-#Region "Machining Property"
+#Region "Tool Property"
 
    ' Variabile che indica quando non lanciare l'update del disegno utensile
    ' (utile per evitare di rifare il disegno più volte quando vengono caricati i parametri alla selezione di un utensile)
@@ -409,14 +409,17 @@ Public Class ToolTreeViewItem
                UpdateSceneToolDraw(DrawUpdateSource.LEN)
             End If
             NotifyPropertyChanged("Len")
-            ' Se lama e len e totlen coincidono tipo piatto
+            ' Se lama
             If (Type And MCH_TF.SAWBLADE) <> 0 Then
                Dim CurrTotLen As Double = 0
-               StringToLen(TotLen, CurrTotLen)
-               If (CurrTotLen - dValue) > 10 * EPS_SMALL Then
-                  Type = MCH_TY.SAW_STD
-               Else
-                  Type = MCH_TY.SAW_FLAT
+               If Not IsNothing(TotLen) Then
+                  StringToLen(TotLen, CurrTotLen)
+                  ' se len e totlen coincidono tipo piatto
+                  If (CurrTotLen - dValue) > 10 * EPS_SMALL Then
+                     Type = MCH_TY.SAW_STD
+                  Else
+                     Type = MCH_TY.SAW_FLAT
+                  End If
                End If
             End If
          End If
@@ -447,12 +450,14 @@ Public Class ToolTreeViewItem
             NotifyPropertyChanged("TotLen")
             ' Se lama e len e totlen coincidono tipo piatto
             If (Type And MCH_TF.SAWBLADE) <> 0 Then
-               Dim CurrLen As Double = 0
-               StringToLen(Len, CurrLen)
-               If (dValue - CurrLen) > 10 * EPS_SMALL Then
-                  Type = MCH_TY.SAW_STD
-               Else
-                  Type = MCH_TY.SAW_FLAT
+               If Not IsNothing(Len) Then
+                  Dim CurrLen As Double = 0
+                  StringToLen(Len, CurrLen)
+                  If (dValue - CurrLen) > 10 * EPS_SMALL Then
+                     Type = MCH_TY.SAW_STD
+                  Else
+                     Type = MCH_TY.SAW_FLAT
+                  End If
                End If
             End If
          End If
@@ -808,7 +813,7 @@ Public Class ToolTreeViewItem
       End Get
    End Property
 
-#End Region    ' Machining Property
+#End Region   ' Tool Property
 
 #Region "Constructors"
 
@@ -975,7 +980,7 @@ Public Class ToolTreeViewItem
       bDrawingError = False
 
       ' Verifico proprietà draw
-      If m_Draw = String.Empty OrElse IsUUID(Path.GetFileNameWithoutExtension(m_Draw)) Then
+      If String.IsNullOrEmpty(m_Draw) OrElse IsUUID(Path.GetFileNameWithoutExtension(m_Draw)) Then
          CreateToolDraw(UpdateSource)
       Else
          EgtSetCurrentContext(IniFile.m_ToolsDbSceneContext)
@@ -1026,7 +1031,14 @@ Public Class ToolTreeViewItem
    ''' </summary>
    Private Function LoadToolHolder() As String
       Dim sHolder As String = String.Empty
-      EgtUILib.GetPrivateProfileString(S_TOOLHOLDER, Head & "." & ExitPar.ToString(), "", sHolder, IniFile.m_sCurrMachIniFilePath)
+      If Type = MCH_TY.SAW_STD Then
+         EgtUILib.GetPrivateProfileString(S_TOOLHOLDER, Head & "." & ExitPar.ToString() & ":SAW_STD", "", sHolder, IniFile.m_sCurrMachIniFilePath)
+      ElseIf Type = MCH_TY.SAW_FLAT Then
+         EgtUILib.GetPrivateProfileString(S_TOOLHOLDER, Head & "." & ExitPar.ToString() & ":SAW_FLAT", "", sHolder, IniFile.m_sCurrMachIniFilePath)
+      End If
+      If String.IsNullOrEmpty(sHolder) Then
+         EgtUILib.GetPrivateProfileString(S_TOOLHOLDER, Head & "." & ExitPar.ToString(), "", sHolder, IniFile.m_sCurrMachIniFilePath)
+      End If
       If String.IsNullOrWhiteSpace(sHolder) Then
          Return String.Empty
       Else