The pop up window for grading a topic does not show screen to enter grade/comment. Instead it shows a smaller window that contains another Sakai window within itself.
As instructor, create gradebook item
In forums, link topic to gradebook item
As student, start a conversation in that forum
As instructor, go into the topic
Next to the new conversation, click grade
The popup window does not allow you enter grades, comments, or even exit that window.
Make sure you also check the 4 places in the statistics pages (see attached screenshots):
-Grade by Topics (both grade popup and the popup when you click the user's name)
-Grade by user (click the details link)
-Grade by user authored