Improve use of fields with sub levels
When users fill in a field with different levels, they loose some time to understand how it works because it is different than other fields :
In the below example, user clic on the field (left side) instead of clicking on the tree on the rights side.
Then, when the choice is done, users have to click in an other area of the page to validate the choice.
So as to improve the time spend, can you move the tree on the right side ? Then, when the choice is done, the size can be reduce to understand that it has been validated.