EDIT

	 * not handled by the editor (e.g. runtime exceptions).

	 * 

	 * The default {@link org.eclipse.ui.statushandlers.WorkbenchErrorHandler}

	 * is not used or extended because we need a handler for specific scenarios

	 * which displays a custom built error dialog.

import java.net.URI;

import java.net.URISyntaxException;

import org.eclipse.jface.dialogs.IInputValidator;

					//FIXME : This should probably go into some ValidatorFactory

					IInputValidator nonEmptyInputValidator = null;

					//FIXME : This is a workaround to not allow empty strings in the 

					//        input dialog for User and Group entities. 

					//        Normally this should be default

					//        behaviour, so we need to discuss whether this handler

					//        should be used to handle the creating new entities of

					//        type other than User and Group.

					//        Once #4348 is fixed this check can be removed.

					if(text.equals("User") || text.equals("Group")) {

						nonEmptyInputValidator = new IInputValidator() {

							public String isValid(String text) {							

								if(text == null || text.isEmpty()) {

									return "Input cannot be empty";

								}

								return null;

							}			

						};

					}

					InputDialog dialog = new InputDialog(HandlerUtil.getActiveShell(event), 

							"Create " + text, 

							"Enter new " + text, "",

							nonEmptyInputValidator); 

import eu.etaxonomy.cdm.api.service.IUserService;

import eu.etaxonomy.taxeditor.model.MessagingUtils;

import eu.etaxonomy.taxeditor.store.CdmStore;

		if(!CdmStore.getService(IUserService.class).userExists(user.getUsername())) {

			MessagingUtils.warningDialog("Username does not exist", this, "Please create or save user '" + user.getUsername() + "' before changing password");

		} else {

			PasswordWizard wizard = new PasswordWizard(user, conversation);

			WizardDialog dialog = new WizardDialog(getLayoutComposite().getShell(), wizard);		

			dialog.open();

		}

		// Disabling the text field since the user entity is immutable

		text_username.setEnabled(false);