Bug 182190 [StatusHandling] [Wizards] getControl assert on wizard page has no message
M6 If you forget to set the control on your wizard page our assert gives no feedback. We need an error message.
bundles/org.eclipse.jface/src/org/eclipse/jface/wizard/WizardDialog.java
backButton = createButton(composite, IDialogConstants.BACK_ID,
                IDialogConstants.BACK_LABEL, false);
        nextButton = createButton(composite, IDialogConstants.NEXT_ID,
                IDialogConstants.NEXT_LABEL, false);
        return composite;
    }
    /**
     * Creates and return a new wizard closing dialog without openiong it.
     * @return MessageDalog
     */
    private MessageDialog createWizardClosingDialog() {
        MessageDialog result = new MessageDialog(getShell(), JFaceResources
                .getString("WizardClosingDialog.title"), 
                null, JFaceResources.getString("WizardClosingDialog.message"), 
                MessageDialog.QUESTION,
                new String[] { IDialogConstants.OK_LABEL }, 0);
        return result;
    }
    /**
     * The Finish button has been pressed.
     */
    protected void finishPressed() {
        
        
         
         
        
        if (wizard.performFinish()) {