Steps to reproduce:

1. Go to Tools > Preferences > General
2. Under Home Page select Use Bookmark
3. Select This Folder to set a bookmark folder as Home Page

Actual:
Bookmark selection menu allows selection of folders.

Expected:
In this case, bookmark selection menu should not allows selection of folders; it doesn't make sense to have a bookmark folder as home page.

Video demo:
https://youtu.be/pc4Unu7_uvk