@Override
	protected JPanel createContent() {

		JPanel mainPanel = new JPanel();
		JButton flipEndiannessBtn = new JButton("flip");
		mainPanel.add(flipEndiannessBtn);

		flipEndiannessBtn.addActionListener(new EndianFlipper());

		return mainPanel;
	}
The only thing in this widget is a button that does the flipping.

@return
Ghidra/Features/Base/src/main/java/ghidra/app/plugin/core/instructionsearch/ui/EndianFlipWidget.java