@Override
	public void actionPerformed(ActionEvent event) {
		int index = projectComboBox.getSelectedIndex();
		if (index < 0) {
			return;
		}

		ProjectLocator projectLocator = projectLocators[index];
		ProjectData pd = project.getProjectData(projectLocator);
		String projectName = projectLocator.getName();
		if (pd == null) {
			Msg.showError(this, getComponent(), "Error Getting Project Data",
				"Could not get project data for " + projectName);
		}
		else {
			treePanel.setProjectData(projectName, pd);
		}
	}
TreeSelectionListener method that is called whenever the value of the selection changes.
@param e the event that characterizes the change.
Ghidra/Features/Base/src/main/java/ghidra/framework/main/AbstractDataTreeDialog.java