Question Dictionaries not being searched well

[KelvinN.]

I have a problem with searching Dictionaries in my program. If I begin a search with Dictionary 0, the search does not look for all possible matches completely in the RichTextBox, but skips to the next Dictionary. How can I solve this? I have created a video of how this problem is happening. Please help, not even one programmer in upwork could solve this problem. Can Microsoft help? Here is the video: https://yadi.sk/i/WWR3E57e3BBJWf

Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load

        Dim i As Integer

        Do While i < 7
            Dim fileName As String = String.Format("dictionary{0}.txt", i)

            If i > 7 Then
                Exit Do
            End If

            Using reader As New StreamReader("C:\Users\Acer\Desktop\WindowsApplication3\WindowsApplication3\App_Data\" + fileName)

                Do Until reader.EndOfStream

                    Dim parts = reader.ReadLine().Split("|"c)
                    ' prepare replacement dictionary object from file content

                    If replacements.ContainsKey(parts(0)) Then
                        replacements(parts(0)).Add(parts(1))

                    Else
                        Dim newWordList As New List(Of String)
                        newWordList.Add(parts(1))
                        replacements.Add(parts(0), newWordList)
                    End If
                Loop
            End Using

            i += 1

        Loop

 End Sub

 

[KelvinN.]

The replacement dictionary is of type:

Private replacements As New Dictionary(Of String, List(Of String))