Hello mhendrickx,
I am sorry to hear that you've run into a difficulty selecting your categories. We've had a few similar reports regarding an issue where a message regarding the option to Select a Leaf category shows, which our engineers are working on resolving at this time. If this is the issue you have encountered, or if you have encountered a differing issue please feel free to file a support case letting us know the details of your experience so we can include that information to our engineers. I will also followup on this forum thread as soon as there is more information regarding this issue.
- Craig