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
* responsibility to call <code>Display.readAndDispatch()</code>
     * to ensure UI responsiveness.
     * 
     * UI state is saved prior to executing the long-running operation and is 
     * restored after the long-running operation completes executing.  Any attempt  
     * to change the UI state of the wizard in the long-running operation will be 
     * nullified when original UI state is restored.
     * 
     */
    public void run(boolean fork, boolean cancelable,
            IRunnableWithProgress runnable) throws InvocationTargetException,
            InterruptedException {
        
        
        Object state = null;
        if (activeRunningOperations == 0) {
			state = aboutToStart(fork && cancelable);
		}
        activeRunningOperations++;
        try {
            if (!fork) {
				lockedUI = true;
			}
            ModalContext.run(runnable, fork, getProgressMonitor(), getShell()
                    .getDisplay());
            lockedUI = false;
        } finally {
            activeRunningOperations--;
            
            if (state != null) {