In grails, I use the mechanism below in order to implement what I'd call a conditional server-side-triggered dialog: When a form is submitted, data must first be processed by a controller. Based on the outcome, there must either be a) a modal Yes/No confirmation in front of the "old" screen or b) a redirect to a new controller/view replacing the "old" screen (no confirmation required).

So here's my current approach:

1. In the originating view, I have a <g:formRemote name="requestForm" url="[controller:'test', action:'testRequest']", update:"dummyRegion"> and a <span id="dummyRegion"> which is hidden by CSS
2. When submitting the form, the test controller checks if a confirmation is necessary and if so, renders a template with a yui-based dialog including Yes No buttons in front of the old screen (which works fine because the dialog "comes from" the dummyRegion, not overwriting the page). When Yes is pressed, the right other controller & action is called and the old screen is replaced, if No is pressed, the dialog is cancelled and the "old" screen is shown again without the dialog. Works well until here.
3. When submitting the form and test controller sees that NO confirmation is necessary, I would usually directly redirect to the right other controller & action. But the problem is that the corresponding view of that controller does not appear because it is rendered in the invisble dummyRegion as well. So I currently use a GSP template including a javascript redirect which I render instead. However a javascript redirect is often not allowed by the browser and I think it's not a clean solution.

So (finally ;-) my question is: How do I get a controller redirect to cause the corresponding view to "break out" of my AJAX dummyRegion, replacing the whole screen again?

Or: Do you have a better approach for what I have in mind? But please note that I cannot check on the client side whether the confirmation is necessary, there needs to be a server call! Also I'd like to avoid that the whole page has to be refreshed just for the confirmation dialog to pop up (which would also be possible without AJAX).

Thanks for any hints!