window.actions.view.visualization.execute();

            window.prepareWindowModeSwitching(); // it only needs to be called once
            let switcher = qid('videoSwitch');
            if (switcher) {
                switcher.controlClass.switchToMode(window.videoModes.C_FULLSCREEN); // or C_WINDOWED or C_FULLWINDOW
            }

To switch visualization on/off, you can call: [code]window.actions.view.visualization.execute();[/code]
It should be accessible in the main window. To change mode of the visualization, you can use:
[code]
window.prepareWindowModeSwitching(); // it only needs to be called once
let switcher = qid('videoSwitch');
if (switcher) {
switcher.controlClass.switchToMode(window.videoModes.C_FULLSCREEN); // or C_WINDOWED or C_FULLWINDOW
}
[/code]

Did it solve what you wanted?

Hi,
Good catch. Added as https://www.ventismedia.com/mantis/view.php?id=21793

I am trying to turn on visualization from an external app I'm developing. When I send the following,

app.player.visualization.active = true

the only thing that happens is the Visualization checkbox gets checked, but nothing else. I want to have the visualization start up in full screen. Can anyone provide some guidance on this?

As always, thanks in advance.