Common/frmDialog: fix cancel button

GUIs.Common/frmDialog.vb

@@ -22,7 +22,7 @@ Public Class frmDialog
         Question
     End Enum
 
-    Public Sub New(pMessageText As String, pTitle As String, pDialogType As DialogType)
+    Public Sub New(pMessageText As String, pTitle As String, pDialogType As DialogType, Optional pCancel As Boolean = False)
 
         ' Dieser Aufruf ist für den Designer erforderlich.
         InitializeComponent()
@@ -31,6 +31,12 @@ Public Class frmDialog
         txtContent.Text = pMessageText
         txtTitle.Text = pTitle
 
+        If pCancel Then
+            CancelButtonVisible()
+        Else
+            CancelButtonInvisible()
+        End If
+
         Select Case pDialogType
             Case DialogType.Success
                 pnlContent.BackColor = Color.LightGreen