excel - VBA - Too Slow with With and selection Command. How Can I optimize it better to run faster?

This is how to remove the selection and to speed up the process:

With Sheets(Currentsheetname).Range("A" & SelRowNumber + 1 & ":A" & lastrow).Validation
    .Delete
    .Add Type:=xlValidateList, AlertStyle:=xlValidAlertStop, Operator:= _
    xlBetween, Formula1:="Remove"

    .IgnoreBlank = True
    .InCellDropdown = True
    .InputTitle = ""
    .ErrorTitle = "Warning"
    .InputMessage = ""
    .ErrorMessage = "Please select a value from the list available in the selected cell."
    .ShowInput = True
    .ShowError = True
End With

Always try to avoid seletction and activation in VBA.