private Component buildFileBytesPanel() {
		JPanel panel = new JPanel(new PairLayout(5, 5));
		panel.setBorder(BorderFactory.createEmptyBorder(5, 7, 4, 5));

		panel.add(new GLabel("File Bytes:"));
		panel.add(buildFileBytesCombo());
		panel.add(new GLabel("File Offset:"));
		panel.add(buildFileOffsetField());

		return panel;
	}
Define the Main panel for the dialog here.
Ghidra/Features/Base/src/main/java/ghidra/app/plugin/core/memory/AddBlockDialog.java