Use DateEdit control, add TopMost for email attachment indexing, use fixed lookupgrid, email indexing objecttype readonly

Global_Indexer/frmStart.vb

@@ -125,10 +125,9 @@ Public Class frmStart
         DragDropForm(e)
     End Sub
     Sub DragDropForm(e As DragEventArgs)
-        Dim frmCollection = System.Windows.Forms.Application.OpenForms
+        Dim frmCollection = Application.OpenForms
         If frmCollection.OfType(Of frmIndexFileList).Any Then
             MsgBox("Please index the active file/mail first!", MsgBoxStyle.Exclamation, "Drag 'n Drop not allowed!")
-            ' TimerCheckDroppedFiles.Start()
             Exit Sub
         End If
         'Erstmal alles löschen