PROBLEM: When I imported my materials, some of them came in as a "Misc" category. How do I edit the category for each material?
RESOLUTION: Right click on the material you wish to move and select "Add to". Choose the appropriate library/category. You may have to delete it from the Misc Category.
After you move the material to the category that you want, it shows "Uncategorized" in the Category column. To get this to show the correct category, hover over the name, then click the ↑ to the right of the category. This will move the material to the current document. Now move up to the document material that was just added, right click "Add To" and choose the library you want it to go in. It then gives you a warning; choose "Replace".