Bug 12884 find strings to externalize - should be cancelable
instead of a busy cursor it should show a progress dialog with cancelation
org.eclipse.jdt.ui/ui/org/eclipse/jdt/ui/actions/FindStringsToExternalizeAction.java
protected void createButtonsForButtonBar(Composite parent) {
			fOpenButton= createButton(parent, OPEN_BUTTON_ID, ActionMessages.getString("FindStringsToExternalizeAction.button.label"), true); 
			fOpenButton.setEnabled(false);
			createButton(parent, IDialogConstants.CANCEL_ID, IDialogConstants.CANCEL_LABEL, false);
		}
		protected void buttonPressed(int buttonId) {
			if (buttonId != OPEN_BUTTON_ID){
				super.buttonPressed(buttonId);
				return;
			}	
			ISelection s= getTableViewer().getSelection();
			if (s instanceof IStructuredSelection){
				IStructuredSelection ss= (IStructuredSelection)s;
				if (ss.getFirstElement() instanceof NonNLSElement)
					openWizard(((NonNLSElement)ss.getFirstElement()).cu);
			}
		}
		private void openWizard(ICompilationUnit unit) {
			try {
				ExternalizeStringsAction.openExternalizeStringsWizard(unit);
			} catch (JavaModelException e) {
				ExceptionHandler.handle(e, 
					ActionMessages.getString("FindStringsToExternalizeAction.dialog.title"), 
					ActionMessages.getString("FindStringsToExternalizeAction.error.message")); 
			}
		}
	}
		
	private static class NonNLSElement{