In Log search (preview) we have on top a description with link "classification" without ''extra class=mime-count' - please add this.
From where we can read about all possible Main/Sub/Extra/Error class in one place? This should be added. In my opinion all this classificators should have a "in" operative who will be show all possible choise and each one should have "i" icon with hint.
That ux will be just better then the right bar with some descriptions.