路由时离子导航栏按钮消失

I have a Ionic application with a nav bar and left side menu. The nav bar contains a "hamburger" button that expands the left side menu. The side menu contains a list of buttons that link to the different content areas of the application. When navigating from the items in the content menu, the content area of the application is updated correctly, and the hamburger icon remains in place in the nav bar. When navigating from a button in the content area, the hamburger icon disppears from the nav bar.I have a Ionic application with a nav bar and l