private void btnUserHandling_Click(object sender, EventArgs e) { //replace the elements from Candidates user controler this.pnlFunctionViewr.Controls.Clear(); var UserHandling = new UserHandling_Home(); this.pnlFunctionViewr.Controls.Add(UserHandling); //change the background color ClearButtonBackground(); btnUserHandling.ForeColor = Color.White; btnUserHandling.BackColor = Color.Orange; }