diff --git a/CompoWindow/CompoParamPage/CompoParamPageVM.vb b/CompoWindow/CompoParamPage/CompoParamPageVM.vb
index 1f80c7a..36b18d1 100644
--- a/CompoWindow/CompoParamPage/CompoParamPageVM.vb
+++ b/CompoWindow/CompoParamPage/CompoParamPageVM.vb
@@ -411,8 +411,13 @@ Public Class CompoParamPageVM
                                                             CompoWindowMap.refCompoSceneHostV.CompoScene,
                                                             SideEntityControlVM.ModeOpt.ENGRAVE)
             SideEntityControl = New SideEntityControlV(m_SideEntityControlVM)
+            If m_SideEntityControlVM.SideEntityList.Count < 1 Then
+               ' eventulmente stamnpare messaggio!
+               ' OmagOFFICEMap.refStatusBarVM.ClearOutputMessage()
+               ' OmagOFFICEMap.refStatusBarVM.SetOutputMessage("Lavorazioni non disponibile", MSG_TYPE.WARNING)
+            End If
          Else
-            SideAngle_IsEnabled = True
+               SideAngle_IsEnabled = True
             Drip_IsEnabled = OmagOFFICEMap.refMainWindowVM.MainWindowM.GetKeyOption(KEY_OPT.UNDER_CUT) And
                              Not String.IsNullOrWhiteSpace(CurrentMachine.sCurrDripSaw)
             FiloTop_IsEnabled = True
diff --git a/OptionPanel/MachiningTab/SplitModeVM.vb b/OptionPanel/MachiningTab/SplitModeVM.vb
index bb523cc..2160540 100644
--- a/OptionPanel/MachiningTab/SplitModeVM.vb
+++ b/OptionPanel/MachiningTab/SplitModeVM.vb
@@ -1718,13 +1718,22 @@ Public Class SplitModeVM
             If Not ModifStartWindow.ShowDialog() Then Return
             ' Modifica della lavorazione
             Dim dUsal As Double = ModifStartWindowVM.GetVal()
-            EgtSetCurrMachining(nOperId)
-            Dim dAddLen As Double = 0
-            EgtGetMachiningParam(MCH_MP.STARTADDLEN, dAddLen)
-            If dAddLen - dOrigUsal < -10 * EPS_SMALL Then Return
-            EgtSetMachiningParam(MCH_MP.STARTADDLEN, dAddLen + dUsal - dOrigUsal)
-            EgtSetInfo(nOperId, INFO_MCH_USER_SAL, dUsal)
-            UpdateMachiningPreview(m_MachiningList(nI).m_nId, True)
+            Dim bRepeat As Boolean = False
+            Do
+               EgtSetCurrMachining(nOperId)
+               Dim dAddLen As Double = 0
+               EgtGetMachiningParam(MCH_MP.STARTADDLEN, dAddLen)
+               If dAddLen - dOrigUsal < -10 * EPS_SMALL Then Return
+               EgtSetMachiningParam(MCH_MP.STARTADDLEN, dAddLen + dUsal - dOrigUsal)
+               EgtSetInfo(nOperId, INFO_MCH_USER_SAL, dUsal)
+               UpdateMachiningPreview(m_MachiningList(nI).m_nId, True)
+               bRepeat = Not UpdateMachiningPreview(m_MachiningList(nI).m_nId, True)
+               If bRepeat Then
+                  EgtSetMachiningParam(MCH_MP.STARTADDLEN, dOrigUsal)
+                  EgtSetInfo(nOperId, INFO_MCH_USER_SAL, dOrigUsal)
+                  dUsal = dOrigUsal
+               End If
+            Loop Until Not bRepeat
             ' verifico interferenza
             EgtVerifyMachining(m_MachiningList(nI).m_nId, m_MachiningList(nI).m_nInterf)
             ColorMachining(m_MachiningList(nI))
@@ -1813,14 +1822,25 @@ Public Class SplitModeVM
             ModifStartWindowVM.SetVal(dOrigUeal)
             If Not ModifStartWindow.ShowDialog() Then Return
             ' Modifica della lavorazione
-            Dim dUsal As Double = ModifStartWindowVM.GetVal()
-            EgtSetCurrMachining(nOperId)
-            Dim dAddLen As Double = 0
-            EgtGetMachiningParam(MCH_MP.ENDADDLEN, dAddLen)
-            If dAddLen - dOrigUeal < -10 * EPS_SMALL Then Return
-            EgtSetMachiningParam(MCH_MP.ENDADDLEN, dAddLen + dUsal - dOrigUeal)
-            EgtSetInfo(nOperId, INFO_MCH_USER_EAL, dUsal)
-            UpdateMachiningPreview(m_MachiningList(nI).m_nId, True)
+            Dim dUeal As Double = ModifStartWindowVM.GetVal()
+            Dim bRepeat As Boolean = False
+            Do
+               EgtSetCurrMachining(nOperId)
+               Dim dAddLen As Double = 0
+               EgtGetMachiningParam(MCH_MP.ENDADDLEN, dAddLen)
+               If dAddLen - dOrigUeal < -10 * EPS_SMALL Then
+                  Return
+               End If
+               EgtSetMachiningParam(MCH_MP.ENDADDLEN, dAddLen + dUeal - dOrigUeal)
+               EgtSetInfo(nOperId, INFO_MCH_USER_EAL, dUeal)
+               UpdateMachiningPreview(m_MachiningList(nI).m_nId, True)
+               bRepeat = Not UpdateMachiningPreview(m_MachiningList(nI).m_nId, True)
+               If bRepeat Then
+                  EgtSetMachiningParam(MCH_MP.ENDADDLEN, dOrigUeal)
+                  EgtSetInfo(nOperId, INFO_MCH_USER_EAL, dOrigUeal)
+                  dUeal = dOrigUeal
+               End If
+            Loop Until Not bRepeat
             ' verifico interferenza
             EgtVerifyMachining(m_MachiningList(nI).m_nId, m_MachiningList(nI).m_nInterf)
             ColorMachining(m_MachiningList(nI))
diff --git a/SideEntityControl/SideEntityControlVM.vb b/SideEntityControl/SideEntityControlVM.vb
index ffc6ec5..12b541d 100644
--- a/SideEntityControl/SideEntityControlVM.vb
+++ b/SideEntityControl/SideEntityControlVM.vb
@@ -1020,6 +1020,8 @@ Public Class SideEntityControlVM
          End If
       Next
 
+      If vJoint.Count < 1 Then Return
+
       If vJoint(0) And vJoint(vJoint.Count - 1) Then
          bJointStart = True
       End If