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
* to allow the wizard to pre-create their page controls prior to opening,
     * so that the wizard opens to the correct size. And finally it
     * shows the first page.
     */
    protected Control createContents(Composite parent) {
        
        
        
        wizard.addPages();
        Control contents = super.createContents(parent);
        
        createPageControls();
        
        showStartingPage();
        return contents;
    }
    /* (non-Javadoc)
     * Method declared on Dialog.
     */
    protected Control createDialogArea(Composite parent) {
        Composite composite = (Composite) super.createDialogArea(parent);
        
        pageContainer = createPageContainer(composite);
        GridData gd = new GridData(GridData.FILL_BOTH);
        gd.widthHint = pageWidth;
        gd.heightHint = pageHeight;
        pageContainer.setLayoutData(gd);
        pageContainer.setFont(parent.getFont());
         
        GridLayout pmlayout = new GridLayout();