I have not used a HD wallet before. This looks really interesting and should be great once finished.

In the Accounts Tab, the top bar can disappear altogether. That is, the top bar is blank when an Account/Address is highlighted (blue) and even when nothing is highlighted. Meaning, both versions of the top bar ((tick, edit, archive, menu) & (logo, +, lock, menu)) are not visible. The condition was temporary and I am not sure what I did before the top bar returned to normal. I could not reproduce the condition. Note that swiping to other tabs and going back to Accounts did not resolve the issue.