@SuppressWarnings("unchecked")
@Override
protected void onEvent(final AjaxRequestTarget target)
{
// Get clicked cursor position
final WebRequest request = (WebRequest)RequestCycle.get().getRequest();
final Map<String, String[]> parameters = request.getParameterMap();
final int x = Integer.parseInt(parameters.get("x")[0]);
final int y = Integer.parseInt(parameters.get("y")[0]);
// Force refresh
imageResource.clearData();