private void staffReportBtn_Click(object sender, EventArgs e)
 {
     if (PnlContainer.Controls.ContainsKey("StaffReport"))
     {
         int index = PnlContainer.Controls.IndexOfKey("StaffReport");
         PnlContainer.Controls[index].BringToFront();
     }
     else
     {
         StaffReport staffReport = new StaffReport();
         staffReport.Dock = DockStyle.Fill;
         PnlContainer.Controls.Add(staffReport);
         staffReport.BringToFront();
     }
 }