Design issues in preferences window

[Kasper Færch Mikkelsen]

I'm using Boostnote v0.8.17 on Ubuntu 17.10 64bit, and found two issues.

• Strange black (check)box at the top of the preferences window.
• "Info: Release Note: v0.8.17" is too large for the sidebar.

[Kohei TAKATA]

@kasperfm
I will close this issue, because this repository is for boostnote-mobile.
Could you open this issue in this repository?