Recently it became possible to post an UNGRADED discussion to a specific section using the "Post to" option. See #4 in image below.
You can create section-specific discussions for ungraded discussions by selecting one or multiple sections in the Post to drop-down menu .
The above is from:
I have a teacher who has been using the discussion feature for several years. She created a discussion and made an understandable mistake by choosing the "Post to" box to choose a specific section of her course. Once she did that, she was no longer able to choose the "Graded" option, which is below the "Post to" option. You have to go back to the "Post to" box and change it back to "All Sections" to get the "Graded" option to be clickable again.
On the other hand, if you were to choose "Graded" first, then the "Post to" option (above) goes away. It would help things a great deal if this were offered on the screen in reverse. That is, put the "Post to" option below the "Options" section that includes "Graded." Also, clarifying that the "Post to" option only applies to UNGRADED discussions would help clear up the confusion.
I have put in a support ticket about this and they are considering it as a "user experience issue." They tell me that they "use cases marked like that in discussions with our development team to help define development priorities." Perhaps I should put this in as a feature request? Although, honestly, I view it as something that is not functioning properly.