How to exclude a combobox from a panel?

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C#

combobox

Initially, only the panels are visible, and then when the user clicks on a button, the panels will disappear and the label, combobox, and button will appear. But the problem I'm having is that only the label and button appear, and the combobox remains invisible.

Initially the combobox, label, and button overlap with the panel and are just made invisible through coding, but I can't understand why the button and label show up but the combobox won't.

private void Form1_Load(object sender, EventArgs e)
        {
            cboIncome.Visible = false;
            lblIncType.Visible = false;
            btnAdd.Visible = false;

        }

        private void btnIncome_Click(object sender, EventArgs e)
        {
            panel1.Visible = false;
            panel2.Visible = false;
            panel3.Visible = false;
            panel4.Visible = false;
            panel5.Visible = false;

            cboIncome.Visible = true;
            lblIncType.Visible = true;
            btnAdd.Visible = true;

        }