Private Sub ComboBox1_KeyDown(ByVal KeyCode As MSForms.ReturnInteger, ByVal Shift As Integer)
IsArrow = KeyCode = vbKeyUp Or KeyCode = vbKeyDown
If KeyCode = vbKeyReturn Then ComboBox1.List = FullList 
End Sub

Private Sub ComboBox1_Change()
    Dim oneItem As Variant
    Dim FilteredItems() As String
    Dim NotFlag As Boolean
    Dim Pointer As Long, i As Long
    
    If DisableMyEvents Then Exit Sub
    If AbortOne Then AbortOne = False: Exit Sub
    If TypeName(FullList) Like "*()" Then
        ReDim FilteredItems(1 To UBound(FullList))
        DisableMyEvents = True
        Pointer = 0
        With Me.ComboBox1
            Select Case FilterStyle
                Case 2: .Tag = LCase(.Text) & "*"
                Case 0: .Tag = "*" & LCase(.Text) & "*"
                Case 1: .Tag = "*" & LCase(.Text) & "*": NotFlag = True
                Case 3: .Tag = "*" & LCase(.Text)
                Case "": .Tag = "*"
            End Select
            
            For Each oneItem In FullList
                If (LCase(oneItem) Like .Tag) Xor NotFlag Then
                    Pointer = Pointer + 1
                    FilteredItems(Pointer) = oneItem
                End If
            Next oneItem
            
            .List = FilteredItems
            .DropDown
        
        DisableMyEvents = False
            If Pointer = 1 Then .ListIndex = 0
        End With
    End If
End Sub

Option Explicit
Public FullList As Variant
Public IsArrow As Boolean
Public totCntParas As Long


Private Sub UserForm_Initialize()

Dim aPar As Paragraph, sList As String, i As Long, sText As String, prghCnt As Integer Dim resultArrayParalist() As String
Dim j As Long

  For i = 1 To ActiveDocument.Paragraphs.Count
  sText = Trim(Trim(ActiveDocument.Paragraphs(i).Range.Text))
    If Split(sText, vbCr)(0) <> "" Then
          sList = sList & i & ","
          FullList = Split(sList, ",")
    End If
  Next i
  
ComboBox1.List = FullList
End Sub

Private Sub ComboBox1_Change()

Dim i As Long, paraNofound As Boolean
Dim oBkMrk As Bookmark
Dim wdActDoc As Document
Set wdActDoc = ActiveDocument

With ComboBox1

If Not IsArrow Then .List = FullList 
If .ListIndex <> -1 And Len(.Text) Then
    For i = .ListCount - 1 To 0 Step -1
            If InStr(1, .List(i), .Text, 1) = 0 Then .RemoveItem i
           
    Next i
   .DropDown
   Call updateRecordsInTbx
End If

If .Text = "" Then txtParaDetails.Text = ""

paraNofound = False
totCntParas = wdActDoc.Paragraphs.Count

For i = 0 To .ListCount - 1
   If .List(i) = .Text Then
   paraNofound = True
   Exit For
   End If
Next i

If Not paraNofound Then
   If .Text <> "" And .Text <= totCntParas Then
   MsgBox .Text & " is Empty Para "
   txtParaDetails.Text = ""
   Else
   MsgBox .Text & " Para No. Does Not Exists "
   txtParaDetails.Text = ""
End If
End If

End With

End Sub

Private Sub ComboBox1_KeyDown(ByVal KeyCode As MSForms.ReturnInteger, ByVal Shift As Integer)

IsArrow = KeyCode = vbKeyUp Or KeyCode = vbKeyDown
If KeyCode = vbKeyReturn Then ComboBox1.List = FullList

End Sub

Public Sub updateRecordsInTbx()

Dim oBkMrk As Bookmark
Dim wdActDoc As Document
Set wdActDoc = ActiveDocument
   
  txtParaDetails.Text = ""
  txtParaDetails.Text = txtParaDetails.Text & wdActDoc.Paragraphs(ComboBox1.Text).Range & vbCrLf

End Sub