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
w.setEnabled(b.booleanValue());
			}
        }
    }
    /**
     * Restores the enabled/disabled state of the wizard dialog's
     * buttons and the tree of controls for the currently showing page.
     *
     * @param state a map containing the saved state as returned by 
     *   <code>saveUIState</code>
     * @see #saveUIState
     */
    private void restoreUIState(Map state) {
        restoreEnableState(backButton, state, "back"); 
        restoreEnableState(nextButton, state, "next"); 
        restoreEnableState(finishButton, state, "finish"); 
        restoreEnableState(cancelButton, state, "cancel"); 
        restoreEnableState(helpButton, state, "help"); 
        Object pageValue = state.get("page"); 
        if (pageValue != null) {
			((ControlEnableState) pageValue).restore();
		}
    }
    /**
     * This implementation of IRunnableContext#run(boolean, boolean,
     * IRunnableWithProgress) blocks until the runnable has been run,
     * regardless of the value of <code>fork</code>.
     * It is recommended that <code>fork</code> is set to
     * true in most cases. If <code>fork</code> is set to <code>false</code>,
     * the runnable will run in the UI thread and it is the runnable's