diff --git a/ToolCollection/frmNIVerknuepfungen.Designer.vb b/ToolCollection/frmNIVerknuepfungen.Designer.vb
index 838448d..c38433d 100644
--- a/ToolCollection/frmNIVerknuepfungen.Designer.vb
+++ b/ToolCollection/frmNIVerknuepfungen.Designer.vb
@@ -1763,6 +1763,7 @@ Partial Class frmNIVerknuepfungen
         '
         'btnLink
         '
+        Me.btnLink.Enabled = False
         Me.btnLink.Image = Global.ToolCollection.My.Resources.Resources.link
         Me.btnLink.ImeMode = System.Windows.Forms.ImeMode.NoControl
         Me.btnLink.Location = New System.Drawing.Point(409, 167)
diff --git a/ToolCollection/frmNIVerknuepfungen.vb b/ToolCollection/frmNIVerknuepfungen.vb
index 051606d..589b1a1 100644
--- a/ToolCollection/frmNIVerknuepfungen.vb
+++ b/ToolCollection/frmNIVerknuepfungen.vb
@@ -560,6 +560,7 @@ Public Class frmNIVerknuepfungen
                     Next
                 End If
 
+                EnableBtnLink()
 
             End If
 
@@ -1393,6 +1394,13 @@ Public Class frmNIVerknuepfungen
         End Try
 
     End Function
+
+    Private Sub EnableBtnLink()
+        btnLink.Enabled =
+            lbxWMIndex.SelectedItems.Count > 0 And
+            (lbxQuelle1.SelectedItems.Count > 0 OrElse txtManIndexwert.Text <> "")
+    End Sub
+
     Private Sub btnLink_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnLink.Click
         ' wenn im ListView ein Element selektiert wurde
         If Me.lvwVerknuepfungen.SelectedItems.Count > 0 Then
@@ -2829,6 +2837,8 @@ Public Class frmNIVerknuepfungen
         Else
             grbFilterDB.Enabled = True
         End If
+
+        EnableBtnLink()
     End Sub
     Private Sub txtGrundgeruest_check_Click(sender As System.Object, e As System.EventArgs) Handles txtGrundgeruest_check.Click
         Me.txtCheckIndexSQL.Text = "SELECT COUNT(*) FROM [%view] WHERE "
@@ -3522,7 +3532,14 @@ Public Class frmNIVerknuepfungen
         If _selectedIndex_Type Is Nothing = False Then
             visinvisible_Vektor_ins_State()
         End If
+
+        EnableBtnLink()
     End Sub
+
+    Private Sub lbxQuelle1_SelectedIndexChanged(sender As Object, e As EventArgs) Handles lbxQuelle1.SelectedIndexChanged
+        EnableBtnLink()
+    End Sub
+
     Sub visinvisible_Vektor_ins_State()
         If _selectedIndex_Type.StartsWith("Vektor") Then
             Me.rbvkt_add.Visible = True