When a new PDF document is opened in the GENERIC viewer we (obviously) create a new `AnnotationEditorUIManager`-instance, since those are document-specific, and thus we need to ensure that we actually register the `editorTypes` for each one.
When a new PDF document is opened in the GENERIC viewer we (obviously) create a new `AnnotationEditorUIManager`-instance, since those are document-specific, and thus we need to ensure that we actually register the `editorTypes` for each one.