Option Explicit
Dim ClickPosition As Variant

Private Sub Text1_Click()
    ClickPosition = Text1.SelStart
End Sub

Private Sub Text1_DblClick()
 
    Dim PosKomma1 As Variant
    Dim PosKomma2 As Variant
 
    PosKomma1 = InStrRev(Text1.Text, ",", ClickPosition)
    PosKomma2 = InStr(ClickPosition, Text1.Text, ",")
 
    Text1.SelStart = PosKomma1
    Text1.SelLength = PosKomma2 - PosKomma1
 
End Sub