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
Point containerSize = new Point(rect.width, rect.height);
        return new Point(Math.max(0, contentSize.x - containerSize.x), Math
                .max(0, contentSize.y - containerSize.y));
    }
    /* (non-Javadoc)
     * Method declared on Dialog.
     */
    protected void cancelPressed() {
        if (activeRunningOperations <= 0) {
            
            
            
            
            setReturnCode(CANCEL);
            close();
        } else {
            cancelButton.setEnabled(false);
        }
    }
    /*
     * (non-Javadoc)
     * @see org.eclipse.jface.window.Window#close()
     */
    public boolean close() {
        if (okToClose()) {
			return hardClose();
		}
        return false;
    }
    /* (non-Javadoc)