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
* @param w the control
         */
        public void setPageLocation(Control w) {
            w.setLocation(marginWidth, marginHeight);
        }
    }
    /**
     * Creates a new wizard dialog for the given wizard. 
     *
     * @param parentShell the parent shell
     * @param newWizard the wizard this dialog is working on
     */
    public WizardDialog(Shell parentShell, IWizard newWizard) {
        super(parentShell);
        setShellStyle(SWT.CLOSE | SWT.MAX | SWT.TITLE | SWT.BORDER
                | SWT.APPLICATION_MODAL | SWT.RESIZE | getDefaultOrientation());
        setWizard(newWizard);
        
        
        cancelListener = new SelectionAdapter() {
            public void widgetSelected(SelectionEvent e) {
                cancelPressed();
            }
        };
    }
    /**
     * About to start a long running operation triggered through
     * the wizard. Shows the progress monitor and disables the wizard's
     * buttons and controls.
     *