Hamburger menu for new notes is unavailable in root note #114

Describe the bug
Hamburger menu for new notes is unavailable in root note. The only way to add child note to root is using "Navigate note tree" in ... menu jump to any child note, then hamburger appears and tapping it brings notes tree on left where root note can be selected but with hamburger on it this time

To Reproduce
Steps to reproduce the behavior:

1. Go to root note, find no hamburger for new notes
2. Click on "Navigate note tree" in '...' menu
3. Jump to any child note in tree, find hamburger there and notes tree on the left
4. Select root note in the tree
5. Finally find hamburger on root note opened

Expected behavior
Hamburger on root note after app startup

Screenshots

Smartphone:

• Device: Xiaomi Mi8
• Android version: 10
• App version: no info in About section, the latest one from Fdroid

Additional context
Can't find any info for what purpose there in hamburger are two new note buttons, in Help "New note" page is empty as well