TextBlock and ListBox is not showing up when I run the program WPF C#

Please help me, I'm confused why it doesn't show up when my other View like cancellation shows up just fine. Can someone help me so that it would show once I click on the Travel History? I would really appreciate who helps. Tell me if you want more details. For now this is the link of the usercontrol and mainwindow.xaml: https://paste.mod.gg/aialvcampztg/0