In Annotation 18.1 the command buttons: OK, Cancel, UI will show only shown in modeling windows appear even though it is pure annotation commands. In the annotation window and the additional 3D window buttons do not appear.
If e.g. be accessed from the Mini toolbar commands with a hidden user interface, it is in the annotation window only by using the space bar and click on the button user interface, to display the user interface.
This is inconsistent from the operator and performs especially for new or inexperienced users always confusing.
See the screenshot. Here in Modeling 2 Display windows were opened, in this case in Annotation a 3D window is displayed permanently, using "side by side" also order visible --> Buttons are only available in windows that do not belong to annotation.