Press the Spacebar.
Note: The page window is split vertically (default) or horizontally (if the frame is larger than higher), and the text is shown on the right side or on the bottom. The I-beam is positioned before on the first word of the selected column.
Change the proportion
Drag the splitter between panes and change the proportion of the space assigned to the page pane and to the text pane.
Bring content of the page in the view
While editing text, to bring content of of the page window, hold ALT and then drag the page where you want.
Switch split direction, or switch to Text Editor from editing "on page"
On the Articles menu, do one of the following:
•Select Switch to Text Editor Horizontal Split
•Select Switch to Text Editor Vertical Split
To learn more, see also