VBA Code

What is currently selected

Returns an object
In VSTO this must be cast to the correct type when using Option Strict On.

Application.Selection.Information = wdInformation.wdActiveEndPageNumber 

Documents

Documents can have several windows and windows can have several panes.
Each document has at least one corresponding window associated with it.
ActiveDocument - Refers to the document that is currently active.
ThisDocument - Refers to the document that contains the code. This is only relevant to document-level solutions. If you have an application-level add-in then this is not relevant.

Windows

Each window contains a Panes collection containing all the corresponding Pane objects

Application.ActiveWindow.Panes(1).Activate 

Panes

Normally a window contains just one pane.
It is however possible to split a window into multiple panes. Each Pane is represented by its own Pane object.

Task Panes

wdTaskPanes.wdTaskPaneHelp 

Application.ScreenRefresh 
Application.KeyBindings - key shortcuts 
Application.RecentFiles - 50 most recently opened 
Application.TaskPanes 
Application.DefaultSaveFormat 

Document.StoryRanges 

Range.TextRetrievalMode.IncludeFieldCodes =