JComboBox error blocking another field display

Question

I have a problem with JComboBox. It's blocking another field in a frame meant to display another value that is linked through a foreign key in a database, a value that depends on the combo box already pop out. But somehow, after the user clicks the combo box it is blocking another field. The app is using MySql.

Here's the code:

ComboBox method to fill value from DB

public void comboBoxBerat(){
        DbConnection DB = new DbConnection();
        DB.DbConnection();
        con = DB.con;
        stat = DB.stmt;
        try {
            sql = "SELECT * FROM weight_of_services";
            rs = stat.executeQuery(sql);
            
            while (rs.next()) {
                jComboBoxBerat.addItem(rs.getString("weight"));
            }
            con.close();                      
        } catch (Exception e) {
            JOptionPane.showMessageDialog(this, e.getMessage());
        }
    }

Action when selection is made from combo box, its get the value that linked with foreign key

private void jComboBoxBeratActionPerformed(java.awt.event.ActionEvent evt) {                                             
        DbConnection DB = new DbConnection();
        DB.DbConnection();
        con = DB.con;
        stat = DB.stmt;
        
        String item = (String)jComboBoxBerat.getSelectedItem();
        String sql = "SELECT price FROM weight_of_services WHERE weight = ?";
        
        try {
            pst = con.prepareStatement(sql);
            pst.setString(1, item);
            rs = pst.executeQuery();
            
            if (rs.next()) {
                String price = rs.getString("price");
                txtHargaBerat.setText(price); //put value from combobox to txtField
            }
            con.close();
        } catch (Exception e) {
        }
    }

The problem after I select from the box its blocking another field.

This is the combo box problem in the frame

Answer 1

It's solved. This because i am using jpanel for customizing color for the frame. Its just so messed up with the stacking one panel on top of the other one. That's why my dropdown list get blocked. So what I did, removed all the panel. Custom and sorting it more carefully and tidy from the start.