The additional actions of an annotation: cursor, mouse button, focus and page events.
public sealed class PdfAnnotationAdditionalActions : PdfAdditionalActions
ISO 32000-2 §12.6.3, Table 197 (PDF 1.2; PO, PC, PV and PI PDF 1.5).
kind:method, kind:property, kind:ctor. Press Esc to clear.BlurGets the action when the annotation loses the input focus (Bl; widget annotations only).CursorEnterGets the action when the cursor enters the annotation's active area (E).CursorExitGets the action when the cursor exits the annotation's active area (X).FocusGets the action when the annotation receives the input focus (Fo; widget annotations only).MouseDownGets the action when the mouse button is pressed inside the active area (D).MouseUpGets the action when the mouse button is released inside the active area (U); the annotation's A takes precedence over it.PageCloseGets the action when the page holding the annotation is closed (PC, PDF 1.5), before the page's own close action.PageInvisibleGets the action when the page holding the annotation is no longer visible (PI, PDF 1.5).PageOpenGets the action when the page holding the annotation is opened (PO, PDF 1.5), after the page's own open action.PageVisibleGets the action when the page holding the annotation becomes visible (PV, PDF 1.5).