From The Document Foundation Wiki
How to display a document in side-by-side page view?
- In a Writer text
- In a Calc spreadsheet
- Approach is explained in this item.
- For other modules
- Select the ▸ . The same file is present in two windows. Changes in one window are automatically reflected in the other window.
- Rearrange the size and position of the windows to get the desired display.
- Under MS-Windows, you can also use the following trick:
- Minimize all windows (shortcut key ⊞ Win+D).
- Enlarge the 2 windows.
- Right-click in the taskbar.
- Select Show windows stacked or Show windows side by side.