Closing a PDF over Raspberry Pi Connect

I have successfully used Raspberry Pi Connect (Beta) to connect my RPi 4 (Debian GNU/Linux 12 (bookworm) and my Ubuntu (24.04 LTS) laptop. I used the touchpad on the laptop to open the File Manager and then the Bookshelf folder and finally the Beginners Guide PDF. The PDF opens and occupies the entire screen, but I cannot figure out how to close the PDF and return to the Pi desktop? If I close the connection and reopen, the PDF returns and not the desktop. I can only get the desktop back if I reboot the Pi and connect again. I’ve tried using the Ctrl, Pi, Alt, Esc, Tab icons in the lower left corner of the window, but they do not seem to do anything. The Pi is headless with no keyboard, mouse or display.