Generating and filling bookmark folders should cause the bookmark menu to rebuild

[alexwykoff]

Did you search for similar issues before submitting this one?
Yes

Describe the issue you encountered:
After creating folders, subfolders, and subsubfolders, it was found that the subfolders and subsubfolders were not appearing in the Bookmarks main menu dropdown. They were visible in the toolbar dropdown and on about:bookmarks.

Expected behavior:
Generating subfolders and subsubfolders should cause the Bookmarks main menu to rebuild so that they may be visible when a user wishes to view them.

• Platform (Win7, 8, 10? macOS? Linux distro?):
  Tested on OS X.
• Brave Version:
  0.12.1 Preview3
• Steps to reproduce:
  1. Created folders, subfolders, and subsubfolders.
  2. Move bookmarks into those folders.
  3. Open the Bookmarks main menu item and attempt to navigate those folders.
• Screenshot if needed:
  
• Any related issues: