Today the U.S. Patent and Trademark Office officially granted Apple a patent that relates to electronic devices that have multiple displays for displaying various content, and user interactions with such devices. Apple's patent illustrates an iPad with dual displays.  

According to Apple, in some embodiments, an electronic device displays and allows user interaction with content on multiple displays. In some embodiments, an electronic device displays three-dimensional content using coordinated views on multiple displays.

In some embodiments, an electronic device shares content while displaying a video conferencing user interface. In some embodiments, an electronic device facilitates the display or keeping private of content on multiple displays.

In some embodiments, an electronic device facilitates the display of information from applications using a shared graphical input coordinate space. In some embodiments, an electronic device presents indications of notifications.

In some embodiments, an electronic device presents representations of items of content that are related to content presented on the one or more electronic devices. In some embodiments, an electronic device presents user interfaces including a soft keyboard.

Apple's patent FIG. 6A below illustrates exemplary device #500 with touch screens 504-1 and 504-2. Touch screens 504-1 and 504-2 optionally display one or more user interfaces that include various content; Oddly FIG. 6P-2 illustrates a side button #622 which triggers the second display to be in touch pad mode.

Apple's granted patent 11,079,995 is a super detailed patent with dozens of patent figures that you could review here.