Keeping a Window Visible on Deskreen While Switching Workspaces in Ubuntu

[rafisics]

I am using Ubuntu 24.04 LTS (X11) and have two application windows open:

1. A text editor for LaTeX writing.
2. A PDF viewer for reference.

I use Deskreen to share the PDF viewer on my iPad as a second display. However, when I switch to a different workspace, the shared window becomes blank on my iPad.

Question:

Is there a workaround to keep the PDF viewer visible on the iPad via Deskreen, even when I switch workspaces on my Ubuntu machine?

What I Tried:

I attempted to create a virtual display using xrandr to extend my Ubuntu screen on iPad, but I didn't succeed. Here are the details of my attempt: #42 (comment).