I am using the Google Documents List Data API 3.0 for .net (documents3 
project)

What steps will reproduce the problem?
1. Create a new document with the web browser.
2. Star the document.
3. Read the document using a DocumentsListQuery on the title (For example)
4. Check the document.DocumentEntry.IsStarred - it should be "true"
5. Put "false" to try to remove the star
6. The star category is not removed from the DocumentEntry.

Please provide any additional information below.
The problem is that the "IsStarred" property is using the "public static 
AtomCategory STARRED_CATEGORY" object created earlier, which is not 
necessarily equal the category inside the collection. In the "Contains" and 
"Find" methods you managed to get over this problem by comparing the 
"scheme" and "term" of the AtomCategory, not using reference "Equals". The 
"Remove" method is not overloaded.
I think an overall better approach would be to override the "Equals" method 
of the AtomCategory class, so it will only check for the "scheme" and 
"term" in the first place. This way the "Contains" and "Find" method need 
not to be overridden, and the "Remove" will just work.
I can easily send in a patch for this, if you'd like.