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
if (currentPage.getControl() == null) {
            currentPage.createControl(pageContainer);
            
            
            Assert.isNotNull(currentPage.getControl());
            
            
        }
        
        currentPage.setVisible(true);
        
        update();
    }
    /**
     * A long running operation triggered through the wizard
     * was stopped either by user input or by normal end.
     * Hides the progress monitor and restores the enable state
     * wizard's buttons and controls.
     *
     * @param savedState the saved UI state as returned by <code>aboutToStart</code>
     * @see #aboutToStart
     */
    private void stopped(Object savedState) {
        if (getShell() != null) {
            if (wizard.needsProgressMonitor()) {
                progressMonitorPart.setVisible(false);
                progressMonitorPart.removeFromCancelComponent(cancelButton);
            }
            Map state = (Map) savedState;