diff --git a/EDMI_ClientSuite/ClassPanelManager.vb b/EDMI_ClientSuite/ClassPanelManager.vb
index b740f3d1..803751bb 100644
--- a/EDMI_ClientSuite/ClassPanelManager.vb
+++ b/EDMI_ClientSuite/ClassPanelManager.vb
@@ -13,7 +13,6 @@ Public Class ClassPanelManager
     Private _dockManager As DockManager
     Private _view As TabbedView
 
-    Private _panels As New List(Of DockPanel)
     Private _documents As New List(Of Document)
 
     Public Sub New(LogConfig As LogConfig, DocumentManager As DocumentManager, DockManager As DockManager)
@@ -38,28 +37,55 @@ Public Class ClassPanelManager
         End Try
     End Sub
 
-
-
     Private Sub View_DocumentDeactivated(sender As Object, e As DocumentEventArgs)
+        Dim oDocument As BaseDocument = e.Document
+        Dim oHashcode As Integer = oDocument.Control.GetHashCode
+
+        If oDocument Is Nothing Then
+            Exit Sub
+        End If
+
         ' Maybe hide panels for this form
+        For Each oPanel As DockPanel In _dockManager.Panels
+            Dim oTag As Integer = oPanel.Tag
+
+            If oTag = oHashcode Then
+                oPanel.Hide()
+            End If
+        Next
     End Sub
 
     Private Sub View_DocumentActivated(sender As Object, e As DocumentEventArgs)
         Dim oDocument As BaseDocument = e.Document
+        Dim oHashcode As Integer = oDocument.Control.GetHashCode
 
         If oDocument Is Nothing Then
             Exit Sub
         End If
 
         ' Show Panels for this form
-    End Sub
-
-    Private Sub View_DocumentClosing(sender As Object, e As DocumentCancelEventArgs)
-        ' close all related panels
         For Each oPanel As DockPanel In _dockManager.Panels
             Dim oTag As Integer = oPanel.Tag
 
-            If oTag = e.Document.Control.GetHashCode() Then
+            If oTag = oHashcode Then
+                oPanel.Show()
+            End If
+        Next
+    End Sub
+
+    Private Sub View_DocumentClosing(sender As Object, e As DocumentCancelEventArgs)
+        Dim oDocument As BaseDocument = e.Document
+        Dim oHashcode As Integer = oDocument.Control.GetHashCode
+
+        If oDocument Is Nothing Then
+            Exit Sub
+        End If
+
+        ' close all related panels. 
+        For Each oPanel As DockPanel In _dockManager.Panels
+            Dim oTag As Integer = oPanel.Tag
+
+            If oTag = oHashcode Then
                 oPanel.Close()
             End If
         Next
@@ -84,16 +110,14 @@ Public Class ClassPanelManager
         _documents.Add(e.Document)
 
         Dim oForm As BaseRibbonForm = e.Document.Control
+        Dim oFormHash As Integer = oForm.GetHashCode
         Dim oInitialPanelInfo As List(Of PanelInfo) = oForm.GetInitialPanels()
 
         ' TODO: determine how much panels at most can be added
         ' check if initial panels should be loaded
         For Each oPanelInfo As PanelInfo In oInitialPanelInfo
-            ' create the panel
-            Dim oPanel = _dockManager.AddPanel(oPanelInfo.Position)
-
             ' create the control
-            Dim oControl As BasePanel = GetPanelControl(oPanelInfo)
+            Dim oControl As BasePanel = GetPanelControl(oPanelInfo, oFormHash)
 
             If oControl Is Nothing Then
                 Dim oPanelType = oPanelInfo.PanelControl.GetType.ToString
@@ -101,14 +125,21 @@ Public Class ClassPanelManager
                 Continue For
             End If
 
-            ' configure the panel
+            ' create panel
+            Dim oPanel = _dockManager.AddPanel(oPanelInfo.Position)
+
+            ' configure panel
             oPanel.Options.ShowCloseButton = oPanelInfo.CanBeClosed
             oPanel.Options.ShowAutoHideButton = oPanelInfo.CanBePinned
             oPanel.Options.ShowMaximizeButton = oPanelInfo.CanBeMaximized
             oPanel.Options.AllowFloating = oPanelInfo.CanBeUndocked
 
-            ' hashcode is needed to know which form a panel belongs to
-            oPanel.Tag = oForm.GetHashCode
+            ' relation is defined through HashCode of form saved in Tag property of panel
+            '
+            ' Form                  Panel
+            ' GetHashCode --------> Tag
+            '
+            oPanel.Tag = oFormHash
             oPanel.Text = oPanelInfo.Title
             oPanel.Controls.Add(oControl)
         Next
@@ -116,7 +147,7 @@ Public Class ClassPanelManager
         ' TODO: establish communication channel to load panels on-demand
     End Sub
 
-    Private Function GetPanelControl(PanelInfo As PanelInfo) As BasePanel
+    Private Function GetPanelControl(PanelInfo As PanelInfo, FormHash As Integer) As BasePanel
         If TypeOf PanelInfo.PanelControl Is DocumentPanel Then
             Dim oPanelControl As DocumentPanel = DirectCast(PanelInfo.PanelControl, DocumentPanel)
             oPanelControl.Datasource = PanelInfo.Datasource
diff --git a/EDMI_ClientSuite/Panels/BasePanel.vb b/EDMI_ClientSuite/Panels/BasePanel.vb
index 86707bbc..46978bc6 100644
--- a/EDMI_ClientSuite/Panels/BasePanel.vb
+++ b/EDMI_ClientSuite/Panels/BasePanel.vb
@@ -1,4 +1,8 @@
 Public Class BasePanel
-
     Public Property Caption As String
+    Public ReadOnly Property OwnerForm As Integer
+        Get
+            Return Parent?.Parent?.Tag
+        End Get
+    End Property
 End Class
diff --git a/EDMI_ClientSuite/Panels/DocumentPanel.vb b/EDMI_ClientSuite/Panels/DocumentPanel.vb
index a1ac3cf3..beca791e 100644
--- a/EDMI_ClientSuite/Panels/DocumentPanel.vb
+++ b/EDMI_ClientSuite/Panels/DocumentPanel.vb
@@ -20,7 +20,9 @@ Public Class DocumentPanel
 
     Private Sub GridViewMain_RowClick(sender As Object, e As RowClickEventArgs) Handles GridViewMain.RowClick
         If e.Button = MouseButtons.Left And e.Clicks = 2 Then
-            MsgBox("Open Preview")
+            MsgBox($"Open Preview for form {OwnerForm}")
+
+            'TODO: Open Preview Panel for OwnerForm
         End If
     End Sub
 End Class