Please create a screencast showing the issue, and send it along temporary login credentials and a link to this thread to help@bricksbuilder.io using the email address you used during the purchase.
Here is the recording:
I think you can easily see whats going on there.
I need to go to another element and comeback to same element and click on the class, and now the class will be auto selected everytime i comeback.
Another video:
Thanks! Ok, all of a sudden I can replicate it 
We’ll update this thread once it’s fixed 
We’ve addressed this in Bricks 2.3.6, now available as a one-click update in your WordPress Dashboard.
Please read the changelog entry before updating, and let us know if you experience any issues.