Description of problem:

Login fails when you hit the Enter key, but succeeds when you click on the Ok button.

Version-Release number of selected component (if applicable):
3.0

How reproducible:
Always

Steps to Reproduce:
1. Open Webadmin
2. Fill username-password and do not leave the password field
3. Hit Enter
  
Actual results:
Login Fails

Expected results:
Login Succeeds

Additional info:
The current behaviour is to call the Default Action when clicking Enter, and the Cancel Action when clicking Escape (see AbstractModelBoundPopupView:44)

This works fine, but when working on a Dialog, if you change the value of a Text Box, and then click Enter without leaving the Text Box, the value in the Box is not flushed to the Model.
This causes a bug on all Dialogs- the most noticed case is the fact that login fails when you hit the Enter key, but succeeds when you click on the Ok button.

To fix this, we need each Editor to pass HasKeyDownHandlers for it's peer widget, so the VIsitor can register a key down listener and set the Model value when Enter is pressed.
The rest will work by itself