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
* The minimum width; <code>0</code> pixels by default.
         */
        public int minimumWidth = 0;
        /**
         * The minimum height; <code>0</code> pixels by default.
         */
        public int minimumHeight = 0;
        /**
         * Creates new layout object.
         *
         * @param mw the margin width
         * @param mh the margin height
         * @param minW the minimum width
         * @param minH the minimum height
         */
        public PageContainerFillLayout(int mw, int mh, int minW, int minH) {
            marginWidth = mw;
            marginHeight = mh;
            minimumWidth = minW;
            minimumHeight = minH;
        }
        /* (non-Javadoc)
         * Method declared on Layout.
         */
        public Point computeSize(Composite composite, int wHint, int hHint,
                boolean force) {
            if (wHint != SWT.DEFAULT && hHint != SWT.DEFAULT) {
				return new Point(wHint, hHint);
			}
            Point result = null;