How do I stop excel from give this message by answer for my users?

"Data may exist in the sheet(s) selection for deletion. To permanently delete the date, Press Delete"


my code is
Sub CopyCells()

    Range("A1:I15").Select
    Selection.Copy
    Sheets.Add
    ActiveSheet.Paste
    Sheets(1).Select
    Sheets(1).Name = "LeaveRequest"
    Cells.Select
    Application.CutCopyMode = False
    With Selection.Interior
        .ColorIndex = 2
        .PatternColorIndex = xlAutomatic
    End With
    ActiveWindow.DisplayHeadings = False
    Sheets("LeaveRequested").Select
    ActiveWindow.SelectedSheets.Delete
    Range("l9").Select
End Sub