Label.wrap doesn't work in development mode

[Evgeny V Mustafin]

public class NewRegAuthAlert extends FlowPanel {
   public NewRegAuthAlert() {
       String html = "For addmin comments please <div id=\"login2\">sign in</div> or register";
       add(new HTML(html));

   }

   protected void onLoad() {
       Label.wrap(DOM.getElementById("login2")).addClickHandler(new ClickHandler() {
           @Override
           public void onClick(ClickEvent clickEvent) {
                Window.alert("alert message");
           }
      });
   }

}

In dev mode this doesn't work. 

java.lang.AssertionError: A widget that has an existing parent widget may not be added to the detach list
	at com.google.gwt.user.client.ui.RootPanel.detachOnWindowClose(RootPanel.java:136)
	at com.google.gwt.user.client.ui.Label.wrap(Label.java:130)

But when compiled works fine. Please help.

[Thomas Broyer]

This is the expected behavior (assertions are disabled by default in prod mode); you're not supposed to use .wrap() that way.

In your case, you can either:

• use an HTMLPanel: grab the text inside the element to construct the Label, then use addAndReplace to replace the <div> with the newly constructed label
  
• add the ClickHandler on the HTML and check the actual target of the ClickEvent to be the <div>
• much simpler and easier to maintain (so, much better for the long term): refactor your code to use UiBinder and put a <g:HTMLPanel>For admin comments please <g:Label ui:field="login2">sign in</g:Label> or register</g:HTMLPanel> with a @UiHandler("login2") to listen to the clicks on the label.