Documents closest to a topic sentence pane edge are central to the topic.
This is a different way of dynamically linking information in related panes, which facilitates understanding of the relationships between a document and multiple topics.
The final pane, below the other panes, is used for top-level forms that have not yet been evaluated.
The contents of these non-container things are shown in the bottom pane.
Similarly, one may observe a pane of glass and the scene behind it.
The topic sentence pane also incorporates document proxies: there is one before each sentence, standing for the document containing that sentence.
The window is separated by divider lines into four panes.
The second and third panes show the current reduction step.
