fix highlighter

Pilz.UI/Highlighter.vb

@@ -320,24 +320,26 @@ Public Class Highlighter
     Private Sub UpdateHighlightPanelBounds()
         Dim bounds As Rectangle = New Rectangle(0, 0, _ContainerControl.ClientRectangle.Width, _ContainerControl.ClientRectangle.Height)
 
-        If TypeOf _HighlightPanel.Parent Is Form Then
-            Dim form As Form = TryCast(_HighlightPanel.Parent, Form)
+        If _HighlightPanel IsNot Nothing Then
+            If TypeOf _HighlightPanel.Parent Is Form Then
+                Dim form As Form = TryCast(_HighlightPanel.Parent, Form)
 
-            If form.AutoSize Then
-                bounds.X += form.Padding.Left
-                bounds.Y += form.Padding.Top
-                bounds.Width -= form.Padding.Horizontal
-                bounds.Height -= form.Padding.Vertical
+                If form.AutoSize Then
+                    bounds.X += form.Padding.Left
+                    bounds.Y += form.Padding.Top
+                    bounds.Width -= form.Padding.Horizontal
+                    bounds.Height -= form.Padding.Vertical
+                End If
             End If
-        End If
 
-        If _HighlightPanel.Bounds.Equals(bounds) Then
-            _HighlightPanel.UpdateRegion()
-        Else
-            _HighlightPanel.Bounds = bounds
-        End If
+            If _HighlightPanel.Bounds.Equals(bounds) Then
+                _HighlightPanel.UpdateRegion()
+            Else
+                _HighlightPanel.Bounds = bounds
+            End If
 
-        _HighlightPanel.BringToFront()
+            _HighlightPanel.BringToFront()
+        End If
     End Sub
 
     Private _DelayTimer As Timer = Nothing
@@ -386,17 +388,6 @@ Public Class Highlighter
         End Set
     End Property
 
-    Public Function CanExtend(ByVal extendee As Object) As Boolean
-        Return (TypeOf extendee Is Control)
-    End Function
-
-    Private Sub SetError(ByVal control As Control, ByVal value As String)
-        Me.SetHighlightColor(control, eHighlightColor.Red)
-    End Sub
-
-    Private Sub ClearError(ByVal control As Control)
-        Me.SetHighlightColor(control, eHighlightColor.None)
-    End Sub
 End Class
 
 Public Enum eHighlightColor