GWT vs Flex vs?

My company is trying to migrate away from a .NET application to something that is purely web-based , and very "ajaxy". The original .NET app is fairly interactive, roughly equivalent to Google Maps as far as user interaction is concerned (zoom, pan, annotate features on a vector map).

Biggest GWT Pitfalls?

I'm at the beginning/middle of a project that we chose to implement using GWT. Has anyone encountered any major pitfalls in using GWT (and GWT-EXT) that were unable to be overcome? How about from a performance perspective?

How to layout widgets using DockLayoutPanel and UiBinder in GWT 2.0?

I'm trying to get a simple layout working under GWT 2.0 using UiBinder. The layout I'm trying to get is one that mimic Java's BorderLayout in where you can specify different panels in the north, south, east, west and center directions; for that I'm using DockLayoutPanel. I would like to get a header and footer, both with fixed width. The remaining viewport space would be occupied by the widget assigned to the DockLayoutPanel center slot.

GWT Custom Event Handler

Can someone give me an example of creating a custom set of an Event and a Handler. Say you have a Person object that you want your widgets to know if it got updated.

How do I create ComboChart in google GWT(Java) with multiple Series and a secondary scale?

Adding Multiple series to the ComboChart with different graph types is straightforward, but I am not able get the targetAxisIndex set against a particular series. Any thoughts/Working examples for this? I looked at the google charting tools javascript examples, but not able to translate the same to Java.

EJB - GWT. Notificate GWT(javaScript) client about some events happened

I want to make document printing service using GWT(javascript+servlet) and EJB. What is the best way to cause EJB to notificate GWT client about some event is happened?

Using GWT"s "shared” folder for storing EJB beans

It is possible to use GWT's "shared" folder for storing beans, that will be used by EJB, GWT servlet and gwt client(javascript) side?

How to allow user to enter only the letters, no numbers and other characters

I want to implement TexBox where user can input only letters. When user enter numbers or invalid characters, near TextBox must appear Error message. Like this: