HexEditor: Allow keydown events to propagate if they are not handled

Author: https://github.com/Zaggy1024
Commit: 76627ec0a2
Pull-request: https://github.com/SerenityOS/serenity/pull/15788
Reviewed-by: https://github.com/ADKaster
Reviewed-by: https://github.com/AtkinsSJ ✅

Userland/Applications/HexEditor/HexEditor.cpp

@@ -468,7 +468,10 @@ void HexEditor::keydown_event(GUI::KeyEvent& event)
         } else {
             text_mode_keydown_event(event);
         }
+        return;
     }
+
+    event.ignore();
 }
 
 void HexEditor::hex_mode_keydown_event(GUI::KeyEvent& event)