If you create a custom category in the classes/variable manager and try to drag and drop an item into the custom category, it will be difficult. Please see the gif below. While it works well for default categories.
We’ve fixed this issue in Bricks 2.0.1, now available as a one-click update in your WordPress Dashboard.
Please take your time to read the changelog entry before updating: Bricks 2.0.1 Changelog – Bricks, and let us know if you continue to experience issues.