diff --git a/local/recipes/tui/tlc/source/src/viewer/mod.rs b/local/recipes/tui/tlc/source/src/viewer/mod.rs
index 4d9d96606b..eaf476bc7e 100644
--- a/local/recipes/tui/tlc/source/src/viewer/mod.rs
+++ b/local/recipes/tui/tlc/source/src/viewer/mod.rs
@@ -1987,6 +1987,18 @@ mod tests {
         assert!(!v.show_help);
     }
 
+    #[test]
+    fn hex_navigation_tab_toggles() {
+        let p = make_hex_file("nav.bin", &[0x01, 0x02]);
+        let mut v = Viewer::open(&p).unwrap();
+        v.mode = ViewMode::Hex;
+        assert!(!v.hexview_in_text);
+        v.handle_key(Key::TAB);
+        assert!(v.hexview_in_text);
+        v.handle_key(Key::TAB);
+        assert!(!v.hexview_in_text);
+    }
+
     fn k(c: char) -> Key {
         Key { code: c as u32, mods: crate::key::Modifiers::empty() }
     }