Does the DualPiP PiP player support full-screen video playback?

DualPiP uses the Document Picture-in-Picture API, which has a browser-enforced maximum window size — full-screen playback in PiP mode is not supported by design. The PiP player window can be resized up to the API's limit but cannot fill the entire screen. For the best viewing experience, maximize the PiP window using the fit-to-screen button. Reference: Document Picture-in-Picture maximum size