Hello there. I have a Lumia 638 and I installed Windows 10 in it after checking from Upgrade Advisor. After using it a bit I detected something. Many apps including Windows utility and basic apps, the navigation/action bar of these apps is not visible, just a small width line and you can barely press them without knowing what's it. It's like, the action bar of these apps is shrink under Windows navigation bar. I can send you snapshots if you want. Is that a well known bug under Microsoft? Kindly help me regarding this issue. Thank you.