I'm trying to figure out a way to place a panel containing combo boxes in my JFrame on a new line using gridbaglayout. At the moment it appears next to another panel of the same type.

Here's what it looks like:

Here is the code for the particular areas

JPanel saleOfferPanel = new JPanel();
JLabel dateOfSale = new JLabel("Select Date of Sale:");     
saleOfferPanel.add(dateOfSale);
JLabel saleDay = new JLabel("Day:");
saleOfferPanel.add(saleDay);
JComboBox<Integer> dayOfSale = new JComboBox<>();
saleOfferPanel.add(dayOfSale);
JLabel saleMonth = new JLabel("Month:");
saleOfferPanel.add(saleMonth);
JComboBox<Integer> monthOfSale = new JComboBox<>();
saleOfferPanel.add(monthOfSale);
JLabel saleYear = new JLabel("Year:");
saleOfferPanel.add(saleYear);
JComboBox<Integer> yearOfSale = new JComboBox<>();
saleOfferPanel.add(yearOfSale);



JPanel endSalePanel = new JPanel();
JLabel endOfSale = new JLabel("Select End Date of Sale:");
saleOfferPanel.add(endOfSale);
JLabel endDay = new JLabel("Day:");
saleOfferPanel.add(endDay);
JComboBox<Integer> endDayOfSale = new JComboBox<>();
saleOfferPanel.add(endDayOfSale);
JLabel endMonth = new JLabel("Month:");
saleOfferPanel.add(endMonth);
JComboBox<Integer> endMonthOfSale = new JComboBox<>();
saleOfferPanel.add(endMonthOfSale);
JLabel endYear = new JLabel("Year:");
saleOfferPanel.add(endYear);
JComboBox<Integer> endYearOfSale = new JComboBox<>();
saleOfferPanel.add(endYearOfSale);

 setLayout(new GridBagLayout());
 GridBagConstraints gbc = new GridBagConstraints();
 gbc.weightx = 0.5;
 gbc.weighty = 0;
 gbc.anchor = GridBagConstraints.NORTHWEST;
 //other panels...

 //panels in question
 gbc.gridx = 0;
 gbc.gridy = 9;
 gbc.gridheight = 1;
 add(saleOfferPanel, gbc);


 gbc.gridx = 0;
 gbc.gridy = 10;
 gbc.gridheight = 1;
 add(endSalePanel, gbc);

Hoping that someone may be able to offer assistance.

Thanks