Can't add to link to folder in bookmark

Something odd I noticed today. I have my bookmarks, and about 6 folders in 
the bookmarks that group other bookmarks. Simple enough. However, when I do 
an "add bookmark" it only shows 5 of the folders. Any clue as to why this 
is? Note, I think something could be funky with that folder as I swear I 
had had around 10 bookmarks in it, and today now it is only about 6. 

Anyone see this before?

Using FireFox 1.0.6
Windows XP SP2