private boolean createHistoryPanel() {
		try {
			historyPanel = new VersionHistoryPanel(tool, null);
			popupActions = historyPanel.createPopupActions();
		}
		catch (IOException ioe) {
			Msg.debug(getClass(),
				"Error creating history panel for versioned file: " + ioe.getMessage(), ioe);
			return false;
		}

		historyPanel.setBorder(BorderFactory.createTitledBorder("Version History"));
		splitPane.setRightComponent(historyPanel);
		historyPanel.addListSelectionListener(e -> {
			if (e.getValueIsAdjusting()) {
				return;
			}
			updateOkTooltip();
		});
		return true;
	}
Return the selected version number from the history panel.
@return -1 if a version history was not selected
Ghidra/Features/Base/src/main/java/ghidra/framework/main/OpenVersionedFileDialog.java