Cleardisplay
Set Visual Cleardisplay [ OFF ]
(Default=On)
This option tells Visual mode not to clear all of display memory before writing the next page of text. Instead, Visual erases enough lines at the start of display memory to make room for the Visual screen. This means that a Home Down will still show you what was last done in Line mode and a Home Up will redisplay the Visual screen. When you press Enter, only the Visual screen is transferred, up to the // template line.
Do not use this option if you only have a couple of pages of display memory, or with hpterm on HP-UX workstations (although it works fine with PC terminal emulators and Qedit/UX).
In Reflection for Windows (versions earlier than 3.70), changing the display width also clears display memory, beyond the control of Set Vis Cleardisplay. If you want to retain your display memory, you also need to use Set Vis Widen Off.